diagnosis dermatology

66. Diagnosis/Dermatology

An 18 year-old young woman comes to the office with a mildly itchy rash on her chest and back for the past two weeks. She noticed an initial area on her back two weeks ago, and now it has spread across her back and chest. On physical examination, she has several salmon-colored plaques with fine scale that follow the cleavage lines of the trunk. Which of the following is the most likely diagnosis?

A. Tinea versicolor

B. Seborrheic dermatitis

C. Psoriasis

D. Pityriasis rosea Explanations

(u) A. Tinea versicolor is a mild infection characterized by hypopigmented macules on the trunk. This eruption is often asymptomatic-usually appearing during humid, warmer temperatures. It is most often on the upper trunk of older teenagers or young adults. Patients may complain of mild pruritis.

(u) B. Seborrheic dermatitis consists of pruritic greasy scales and underlying erythematous patches or plaques on the scalp, central face, presternal areas, and upper back.

(u) C. Psoriasis is characterized by chronic, recurring, erythematous papules and plaques with thick silvery white scale on the elbows, knees, and scalp.

(c) D. Pityriasis rosea is an acute eruption of fine scaling fawn-colored papules and plaques that are distributed along the cleavage lines of the trunk, often referred to as a Christmas tree pattern. A single plaque, called a herald patch, precedes the secondary eruption by 1-2 weeks.

ClinicalIntervention/Dermatology

A 3 year-old child playing in an abandoned shed is bitten by a black widow spider. The mother rushes the child to the emergency department within 20 minutes of the incident. Which of the following if the best initial intervention?

A. Intramuscular steroids

B. Administration of antivenin

C. Immediate immersion in a cold bath

D. Hospital admission for symptomatic care Explanations

(u) A. The bite of this spider does not cause an inflammatory reaction; therefore, steroids are not indicated.

(u) B. Administration of antivenin should be administered to patients with severe envenomation manifested as seizures, respiratory failure, or hypertension.

(u) C. Application of an icepack initially would be helpful for pain relief, however, immersion in a cold bath may cause hypothermia.

(c) D. Hospital admission for symptomatic care should be considered in children, pregnant women, and patients with preexisting cardiovascular disease.


A 26 year-old female comes to the office for evaluation of a painful lump on her right buttock for the past week. Initially, it was a firm, tender nodule that has increased in size and tenderness in the past two days. On physical examination of the right buttock, there is a 3-cm fluctuant tender red nodule. Which of the following is the most appropriate initial intervention?

A. Incision and drainage

B. Mupirocin ointment

C. Systemic antibiotics

D. Moist compresses Explanations

(c) A. Incision and drainage is the mainstay of therapy for abscesses.

(u) B. Individuals may be chronic carriers of S. aureus. Mupirocin ointment is effective in eliminating nasal carriage

of S. aureus.

(u) C. In healthy individuals, incision and drainage is generally adequate therapy for abscesses. Systemic antibiotics may speed the healing of the tissue, and is instituted after incision and drainage of the abscess.

(u) D. Application of moist heat can localize or consolidate the abscess when the furuncle is firm and non-fluctuant aiding in the development and drainage of the abscess.

Clinical Intervention/Dermatology

A 28 year-old female with diabetes mellitus type 2 sustains a partial thickness burn to her left upper arm and her chest when hot grease spilled on her at home. The burn to her arm is circumferential and the estimated total body surface burned is 18%. She has no allergies. The most appropriate treatment of this patient would include

Answers

A. outpatient application of silver sulfadiazine.

B. debridement of all intact blisters.

C. IV cefazolin (Ancef, Kefzol).

D. transfer to a burn center. Explanations

(u) A. Although treatment may include silver sulfadiazine dressings, this patient should not be treated as an outpatient. Also see D for explanation.

(u) B. Debridement of intact blisters remains controversial, however many authorities recommend leaving intact blisters intact and only debride ruptured blisters.

(u) C. If used in the care of a burn patient, the antibiotic selected should have activity against Pseudomonas and S. aureus. Cefazolin does not have any antipseudomonal activity.

(c) D. Reasons for transfer to a burn center include a partial thickness burn covering greater than 10% of total body surface area. In addition, burns in patients with pre-existing medical conditions, such as diabetes, that could complicate their management, prolong recovery, or affect their outcome, is also a reason for transfer to a burn center.


A 28 year-old male presents with burns sustained from hot grease splashed on his left hand earlier this afternoon. The burn extends from his palm to the volar aspect of his wrist and has an erythematous base, covered by an intact blister. There are a few small scattered blisters over the dorsum of the left hand. Which of the following is the initial intervention of choice?

A. Tetanus prophylaxis

B. Admission to a burn unit

C. Intravenous fluid administration

D. Debridement of blisters Explanations

(c) A. Tetanus prophylaxis should be initially considered in all burn patients.

(u) B. Admission to a burn unit is not indicated for adult patients with uncomplicated partial thickness burns covering less than 15 to 20% of total body surface area (TBSA). (u) C. DIV fluids are indicated for severe partial thickness burns covering more than 10% TBSA or in burns with complications. (u) D. Debridement of blisters is controversial, however blisters on the palms and soles should remain intact.


A 36 year-old female comes to the office because a mole on her left calf has changed. On physical examination of the left posterior lower leg, there is a 12 mm, asymmetrical, variegated blue-black macule with raised pink plaque in the upper half of the lesion. Which of the following is the most appropriate clinical management of this lesion?

A. Cryosurgery

B. Topical retinoids

C. Excisional surgery

D. Topical chemotherapy Explanations

(u) A. Physical destruction of suspected melanoma should never be used because histologic verification of the diagnosis cannot be performed.

(u) B. Chronic use of topical retinoids may be effective for superficial solar keratoses.

(c) C. Surgical excision of suspected melanoma is necessary for histologic diagnosis and treatment of the lesion.

(u) D. Topical chemotherapy, such as 5-Fluorouracil, is an effective treatment for squamous cell carcinoma.


A female patient presents with a few common warts on her hands. She has tried over-the-counter preparations with little success and desires something that might work quicker, but has the least chance of scarring. Which of the following is the most appropriate intervention to accomplish this goal?

A. cryosurgery

B. dermabrasion

C. electrosurgery

D. topical acyclovir Explanations

(c) A. Cryosurgery with liquid nitrogen is effective treatment for common warts and has less of a chance of scarring than electrosurgery.

(u) B. Dermabrasion is a technique primarily utilized in the treatment of pitted acne scars and does not play a role in treatment of common warts. (u) C. Electrosurgery is more effective in treatment of common warts, but has a greater chance of scarring than cryosurgery.

(u) D. Topical acyclovir may be indicated in treatment of herpes simplex viral infections, but is not used to treat common warts caused by human papillomaviruses.


A mother brings in her 3 month-old infant and states that she has noticed a rash on her infant's scalp. Physical examination reveals the presence of erythematous and scaling crusty lesions involving the vertex of the scalp. Which of the following is the most appropriate initial intervention?

A. selenium sulfide shampoo

B. permethrin 1% cream rinse

C. warm olive oil compresses

D. scrubbing of scalp with hexachlorophene Explanations

(u) A. While selenium sulfide shampoos can be used in treatment of scalp seborrheic dermatitis in adults, it is not recommended for use in infants and young children.

(u) B. Permethrin 1% cream rinse is utilized in the treatment of pediculosis, not seborrheic dermatitis. (c) C. This infant most likely has scalp seborrheic dermatitis ("cradle cap"). Initial treatment consists of warm olive oil compresses to remove any crusts followed by use of baby shampoo or mild hydrocortisone cream.

(u) D. Hexachlorophene is a bacteriostatic skin cleanser which is not indicated in the treatment of seborrheic dermatitis. It is also not recommended for use in infants and young children.


An elderly woman presents to your clinic complaining of unilateral facial pain and painful lesions. She also complains of blurred vision in the ipsilateral eye. On examination she has several vesicles on an erythematous base, some of the lesions with crusts. They are distributed in a dermatomal pattern and involve the skin overlying the maxillary region and the tip of her nose. Which of the following is the next most appropriate intervention in the care of this patient?

64

Answers

A. KOH prep

B. Culture for bacteria

C. Referral to an ophthalmologist

D. Application of corticosteroids Explanations

(u) A. A KOH prep examining for fungal elements is not indicated in this case.

(u) B. While bacterial infection may occur along with the viral infection, a bacterial culture is not usually employed.

(c) C. Immediate referral to an ophthalmologist is needed when herpes keratitis is suspected, as in this case. A fluorescein stain of the eye might reveal the typical dendritic corneal lesion.

(h) D. Application of corticosteroids may cause proliferation of the virus and should only used by an ophthalmologist


An elderly woman presents to your clinic complaining of unilateral facial pain and painful lesions. She also complains of blurred vision in the ipsilateral eye. On examination she has several vesicles on an erythematous base, some of the lesions with crusts. They are distributed in a dermatomal pattern and involve the skin overlying the maxillary region and the tip of her nose. Which of the following is the next most appropriate intervention in the care of this patient? A. KOH prep

B. Culture for bacteria

C. Referral to an ophthalmologist

D. Application of corticosteroids Explanations

(u) A. A KOH prep examining for fungal elements is not indicated in this case.

(u) B. While bacterial infection may occur along with the viral infection, a bacterial culture is not usually employed.

(c) C. Immediate referral to an ophthalmologist is needed when herpes keratitis is suspected, as in this case. A fluorescein stain of the eye might reveal the typical dendritic corneal lesion.

(h) D. Application of corticosteroids may cause proliferation of the virus and should only be used by an ophthalmologist.


A patient sustained a 6 cm laceration on his anterior tibia that was primarily closed in the emergency department. What is the most appropriate time frame for removal of these sutures?

A. 1-2 days

B. 3-5 days

C. 6-8 days

D. 7-14 days Explanations

(u) A. See D for explanation.

(u) B. See D for explanation.

(u) C. See D for explanation.

(c) D. Suture removal is based upon the area of the body that was sutured. Facial sutures are placed for 3-4 days, scalp sutures for 5-7 days, trunk sutures are placed for 6-8 days, and sutures on the extremity are placed for 7-14 days. Sutures on the extremities can stay for longer periods of time if the area is under maximal tension.


As a general rule, sutures in the face should be removed in

A. 3 days.

B. 5 days.

C. 7 days.

D. 10 days. Explanations

(u) A. See B for explanation.

(c) B. Sutures of the face should be removed in 5 days in order to allow for adequate healing and to limit the amount of scarring. (u) C. See B for explanation.

(u) D. See B for explanation.


Which of the following interventions is the treatment of choice for actinic keratosis?

A. Mohs surgery

B. Cryotherapy

C. Acid peels

D. Radiation therapy Explanations

(u) A. Mohs surgery and radiation therapy are not indicated in the treatment for actinic keratosis.

(c) B. Cryotherapy is the treatment of choice for isolated superficial actinic keratosis.

(u) C. Acid peels can be used to treat actinic keratosis but are not the treatment of choice.

(u) D. See A for explanation

ClinicalTherapeutics/Dermatology

A 16 year-old female comes to the office because her acne has become more severe and she would like to discuss treatment. She was originally prescribed topical clindamycin gel 1 year ago to treat open and closed comedones on her face. Despite regular use of the medication, she now has several comedones and papulopustules across her nose, cheeks, chin and forehead. Which of the following would be an appropriate additional treatment for moderate acne?

A. Intralesional steroids

B. Oral doxycycline

C. Benzoyl peroxide gel

D. Metronidazole cream Explanations

(u) A. Intralesional steroids can be used as an adjunct treatment for large cystic lesions.

(c) B. For moderate acne, oral antibiotics are added to the topical medications treatment regimen.

(u) C. For mild acne, benzoyl peroxide gel can be used alone or in combination with topical antibiotics and/or topical retinoids.

(u) D. Metronidazole cream is a treatment for rosacea.


A 45 year-old female presents to the emergency department with generalized, hot, erythema of the skin. Physical exam reveals an oral temperature of 102 degrees Fahrenheit, purulent conjunctivitis, and mucosal erosions. Her skin is painful and separates from the dermis with touch. Which of the following is the most likely cause for this condition?

A. Ampicillin

B. Prednisolone

C. Aspirin

D. Hydrochlorothiazide (HCTZ) Explanations

(c) A. Medications are most frequently implicated in toxic epidermal necrolysis. These usually include, analgesics (NSAIDs), antibiotics (Ampicillin) and anticonvulsants (Carbamazepine).

(u) B. Systemic glucocorticoids may be used early in the treatment of this condition and are not a cause. (u) C. Aspirin is not linked to toxic epidermal necrolysis.

(u) D. Hydrochlorothiazide diuretics are not associated with the production of toxic epidermal necrolysis.


A patient presents with 3 weeks of worsening pruritic rash located on the upper extremities and interdigital spaces. He is a migrant farm worker with no history of skin disorders. Examination reveals excoriated, erythematous papules with numerous 3-4 mm long, narrow tracts spreading from the papules. What is the best treatment for this patient?

A. Permethrin (Nix)

B. Prednisone (Deltasone)

C. Montelukast (Singulair)

D. Pimecrolimus (Elidel) Explanations

(c) A. Permethrin is used to kill the scabies mite. (u) B. Corticosteroids have no affect on mites.

(u) C. Montelukast would possibly provide symptomatic relief but would not be curative for scabies.

(u) D. Pimecrolimus has no affect on destruction of mites.


Pharmacologic treatment of a cat bite in the person with no allergies consists of which of the following?

Answers

A. Trimethoprim-sulfamethoxazole (Bactrim)

B. Cephalexin (Keflex)

C. Ceftriaxone (Rocephin)

D. Amoxicillin-clavulanate (Augmentin) Explanations

(u) A. See D for explanation.

(u) B. See D for explanation.

(u) C. See D for explanation.

(c) D. Amoxicillin-clavulanate (Augmentin) has activity against Pasteurella multocida which is the causative agent in the majority of cat bite infections.


What scabicide has been associated with neurotoxicity in infants and young children?

A. lindane (Kwell)

B. crotamiton (Eurax)

C. 10% sulfur ointment

D. permethrin (Elimite) Explanations

(c) A. Lindane (Kwell) is concentrated in the CNS and toxicity from systemic absorption in infants has been reported. (u) B. Crotamiton (Eurax) is not associated with CNS toxicity and is an effective scabicide. Its primary side effects include dermatitis and conjunctivitis.

(u) C. Sulfur ointment is no longer used because newer agents have been developed and is not neurotoxic.

(u) D. Permethrin (Elimite) is the drug of choice for the treatment of scabies and is not associated with neurotoxicity.


Which of the following is considered the antibiotic of choice in the treatment of human bite wounds?

A. Ampicillin

B. Penicillin

C. Augmentin

D. Ciprofloxacin Explanations

(u) A. See C for explanation.

(u) B. See C for explanation

(c) C. Augmentin is considered to be the antibiotic of choice for human bites that may be contaminated with Eikenella corrodens, strep viridans, and staph aureus.

(u) D. See C for explanation.

Diagnosis/Dermatology

A 30 year-old patient is seen for a non-painful mass on the upper back which has grown slowly over the past year. He denies previous trauma, drainage from the area or history of dermatologic diseases. Examination reveals a four centimeter firm, but highly mobile subcutaneous mass with no overlying skin discoloration or punctum with drainage. Which of the following is the most likely diagnosis?

A. Epidermoid cyst

B. Hemangioma

C. Keratoacanthoma

D. Lipoma Explanations

(u) A. An epidermoid cyst is a lesion of the dermis, usually with periodic expression of sebaceous material.

(u) B. A hemangioma is typically a discolored elevated bed/mass of vessels penetrating to or through the epidermis.

(u) C. Keratoacanthoma is rapid in its development, more common in the elderly and confined to the dermis. Resembles squamous cell carcinoma.

(c) D. A lipoma is a benign fatty tumor usually developing slowly in the subcutaneous layer and generally remaining small though can become very large.


A 43 year-old woman presents with episodes of facial flushing with increased skin temperature followed by the development of tiny papules and pustules primarily on her cheeks and chin. These symptoms worsen when she eats spicy foods. On examination, telangiectasia are noted along the nasal folds and tiny pustules on both cheeks. Which of the following is the most likely diagnosis?

A. Atopic dermatitis

B. Rosacea

C. Lupus

D. Acnevulgaris Explanations

(u) A. Atopic dermatitis is characterized by chronic dry skin, and pruritic inflammatory lesions of the flexor surfaces of the body. Repeated rubbing or scratching of the skin causes excoriations and lichenification. Atopic dermatitis is often associated with a personal or family history of allergic rhinitis or asthma.

(c) B. Rosacea is chronic, episodic flushing of the face followed by the development of tiny papules and pustules. Eating spicy foods or drinking hot liquids or alcohol can cause exacerbation of the symptoms.

(u) C. The rash associated with lupus is commonly found on the cheeks and not on the chin. There are not typically pustules or telangiectasia noted.

(u) D. Acne vulgaris does not present with facial flushing and would not be triggered by the consumption of spicy foods.


A 55 year-old female presents with a lesion on her face that is painful, bright red, with distinct raised borders. She also is complaining of fever and chills. There is no evidence of any marks which would show a portal of entry. Which of the following is the most likely diagnosis?

A. Impetigo

B. Erythrasma

C. Cellulitis

D. Erysipelas Explanations

(u) A. Impetigo is a bacterial infection of the skin that is associated with honey- colored crusts.

(u) B. Erythrasma is a bacterial infection of the skin that is red in appearance and fluoresces a coral red color under a Wood's lamp. Systemic symptoms are rarely seen and the borders tend to be less distinct.

(u) C. Cellulitis has many features of erysipelas but it goes on to involve the subcutaneous tissues. Patients with cellulitis will not have raised borders and demarkation from uninvolved skin is not distinct with this condition.

(c) D. Erysipelas is a distinct type of superficial cellulitis with redness, a distinct and raised border, and sharp demarkation from uninvolved skin. It is typically associated with systemic symptoms such as fever and chills. It is caused by group A strep most commonly.


A 56 year-old, right hand dominant, carpenter presents to your clinic complaining of a prolonged bruise under his left thumbnail. He states that he first noticed it one year ago. Physical examination reveals a nontender left thumb with a 6 mm macular lesion located under the distal nail bed. It is mixed dark brown and black in color, with irregular borders. The most likely diagnosis is

Answers

A. lentigo.

B. trauma.

C. melanoma.

D. nevus. Explanations

(u) A. Lentigos are typically uniform in color with well-demarcated borders.

(u) B. If the lesion was from trauma, it should have resolved well before one year.

(c) C. Acral lentiginous melanoma may occur on the palm, sole, nail bed, or mucus membrane. This lesion is suspicious for a melanoma due to its irregular borders, being variegated in color, and its size. A biopsy is required and will insure the diagnosis.

(u) D. A nevus usually has regular, well- demarcated borders.


A 60 year-old male presents with a slowly developing facial lesion first noticed 4-5 months ago. He describes it as non-painful and non- pruritic but notes it to be extremely scaly. He denies a history of similar lesions or dermatologic disease. Examination reveals a one centimeter, firm nodule at the right temple with heavy keratinization. There is no fluctuance or skin discoloration. Which of the following is the most likely diagnosis?

A. Actinic keratosis

B. Squamous cell cancer

C. Granuloma annulare

D. Merkel cell carcinoma Explanations

(u) A. Actinic keratosis lesions can be very scaly but are generally flat in appearance not nodular.

(c) B. This is a very typical scenario for a squamous cell cancer occurring in a sun exposed area, with slow development and heavy keratinization.

(u) C. Granuloma annulare is a self-limited dermatosis occurring primarily on the distal extremities is more common in young adults and children.

(u) D. Merkel cell carcinoma lesions are typically discolored and non-keratinizing.


A 65 year-old male presents with multiple lesions on his back. He denies any pruritis. Physical examination reveals the presence of multiple scattered brown plaques with a raised, warty surface that appear to be stuck onto the skin and feel greasy. Which of the following is the most likely diagnosis?

A. lentigines

B. actinic keratosis

C. keratoacanthomas

D. seborrheic keratosis Explanations

(u) A. Lentigines most commonly are seen on the dorsum of the hand and appear as flat brown spots, often with sharp borders.

(u) B. Actinic keratosis usually present as small patches of flesh-colored, pink or yellow-brown lesions often with an erythematous component. The lesions are better felt than seen, having a rough, sandpaper feel and are often tender to palpation.

(u) C. Keratoacanthomas usually occur as an isolated lesion on the face appearing as an erythematous, dome- shaped nodule with a central keratinaceous plug.

(c) D. Seborrheic keratosis is a common benign plaque in the elderly that characteristically has a velvety or warty surface associated with a stuck on appearance and greasy feel.


A mother brings a 3 month-old infant to the office because she is concerned about a red, vascular, nodular growth on the child's back. It appears to be enlarging slightly and the vessels are slightly dilated. It seems to cause the child no discomfort. The most likely diagnosis is

A. a hemangioma.

B. a pigmented nevus.

C. a salmon patch (stork bite). D. a malignant melanoma. Explanations

(c) A. A hemangioma is a bright red to deep purple vascular nodule or plaque that often develops at birth, may enlarge, and may regress and disappear with aging.

(u) B. A pigmented nevus is not a vascular lesion.

(u) C. A salmon patch is a light red macule over the nape of the neck or the glabella.

(u) D. A malignant melanoma presents as a hyperpigmented, asymmetric lesion with irregular borders and is typically

seen in the adult population.


A mother brings in her 2 year-old child stating that the child has had a 3-day history of a nonproductive cough, thick copious rhinorrhea, conjunctivitis, and a fever to 103 degrees. Physical examination reveals a well-hydrated child, with numerous 1-2 mm white papules on both buccal mucosa, normal heart and breath sounds. This presentation is most consistent with early Answers

A. rubeola.

B. rubella.

C. varicella.

D. streptococcal pharyngitis Explanations

(c) A. Rubeola (measles) is characterized by cough, coryza, and conjunctivitis, along with a fever as a prodrome. Koplik spots appear prior to the onset of the typical erythematous, maculopapular rash and are pathognomonic for rubeola.

(u) B. See A for explanation.

(u) C. See A for explanation.

(u) D. See A for explanation.


A patient presents with loss of pigmentation on the back of hands, face, and body folds due to the absence of epidermal melanocytes. There has been improvement with PUVA treatment. Which of the following is the most likely diagnosis?

A. Pityriasis alba

B. Tinea versicolor

C. Vitiligo

D. Melasma Explanations

(u) A. Pityriasis alba is caused by dermal inflammation that becomes scaly and hypopigmented.

(u) B. Tinea versicolor is a fungal infection of the skin presenting as oval or circular lesions

(c) C. Vitiligo is the acquired loss of pigmentation due to the absence of epidermal melanocytes presenting on the back of hands, face, or body folds.

(u) D. Melasma is an acquired brown hyperpigmentation involving the face and neck in women during their second or third trimester of pregnancy.


A patient presents with profound itching. Examination reveals short, reddish lesions on the wrists, elbows, and finger webs. Papules are also noted in these areas. There appears to be burrow marks emanating proximal to the finger webs. Which of the following is the most likely diagnosis?

A. Scabies

B. Body lice

C. Rocky Mountain Spotted Fever

D. Lyme Disease Explanations

(c) A. Scabies is an infestation of a mite that is usually spread by skin to skin contact. Patients present with intractable pruritus, often with minimal cutaneous findings. There may be an associated inflammatory papule or nodule along with a burrow that is sometimes seen early in the course of the infestation.

(u) B. Body lice or pediculosis pubis is an infestation of hair- bearing regions, most commonly in the pubic area but may also be seen on hairy parts of the chest, axillae, and upper eyelashes. It is characterized by mild to moderate pruritus, papular urticaria, and excoriation.

(u) C. Patients develop Rocky Mountain Spotted Fever after a tick bite. It is classically associated with a sudden onset of fever, severe headache, myalgia, and a characteristic acral exanthem. (u) D. Lyme disease is associated with an oval shaped skin lesion with central clearing known as erythema chronicum migrans. It occurs following a tick bite and may be associated with Bell's palsy, arthralgias, and heart block.


A young child is brought to the clinic because the mother noticed a rash while bathing the child. There is a very red slightly raised eruption on the child's face across both cheeks. The child has been in good health and does not appear ill today. The most likely diagnosis is

A. scarlet fever.

B. rubella.

C. roseola.

D. erythema infectiosum. Explanations

(u) A. Scarlet fever is associated with fever, pharyngitis, and "sandpaper rash" over face, neck, trunk, and extremities.

(u) B. Rubella presents with round or oval maculopapular lesions that begin on the neck or face and spread to the extremities.

(u) C. Roseola presents with a high fever with few symptoms, followed by the appearance of a macular rash over the trunk and neck.

(c) D. Erythema infectiosum is generally asymptomatic, presenting with red papules on the face that coalesce to give a "slapped cheek" appearance.

DiagnosticStudies/Dermatology

A 13 year-old child presents with a lesion on his right forearm that is occasionally pruritic. On examination, a 2 cm ring of erythema with a scaly border and central clearing is noted. A suspected diagnosis is confirmed by the presence of

A. a positive patch test.

B. hyphae on a KOH prep.

C. gram-positive cocci on Gram stain.

D. multinucleated cells on Tzanck smear. Explanations

(u) A. Patch testing is positive with allergic dermatitis, not fungal disorders.

(c) B. Ring-shaped lesions with scaly borders and central clearing are most likely caused by fungal infection. Microscopic examination of scrapings reveals hyphae on KOH prep.

(u) C. A positive Gram stain is found with bacterial skin infections, not fungal.

(u) D. Multinucleated cells found on Tzanck smear indicate herpes, not fungal infections.

Diagnostic Studies/Dermatology

A 23 year-old African American female presents with concern regarding "lightening" of the skin in her knees, face, clavicles, and wrists. These areas appear to be increasing in size. She was recently diagnosed with pernicious anemia. In order to confirm her diagnosis, which of the following tests is indicated?

A. Wood's light

B. KOH prep

C. Skin biopsy

D. Gram stain Explanations

(u) A. Wood's light is primarily used to evaluate macules but there are no pathognomonic fluorescent patterns that would confirm the diagnosis of vitiligo.

(u) B. KOH prep would be indicated to search for tinea versicolor by showing a spaghetti and meatball appearance but this patient's condition is consistent with vitiligo.

(c) C. Skin biopsy in a patient with vitiligo will show complete absence of melanocytes and will confirm the diagnosis.

(u) D. Gram stain is helpful in diseases secondary to a bacterial etiology not vitiligo.


A 26 year-old female presents with several pruritic lesions on her dorsal forearms. The lesions are erythematous with vesicles, with a few beginning to weep. She works in a photography laboratory, but denies any other possible exposures. Which of the following is the most useful diagnostic test?

A. VDRL serology

B. KOH prep

C. Patch testing

D. Gram's stain Explanations

(u) A. VDRL serology is useful in the diagnosis of syphilis, not contact dermatitis.

(u) B. KOH prep is used for diagnosis of fungal infections, not contact dermatitis. (c) C. Patch testing with a suspected agent is usually positive in cases of allergic contact dermatitis.

(u) D. Gram's stain is useful in the diagnosis of bacterial infections, not contact dermatitis.


A 26 year-old male complains of intense itching, especially at night and after hot showers, for the past 4 days. On physical examination he has a few red papules and areas of excoriation on his volar wrists, between his fingers, and around his waist. Proper diagnosis should include which of the following tests?

Answers

A. KOH prep

B. Gram stain

C. Skin scraping microscopy

D. Tzanck prep Explanations

(u) A. A KOH prep would be used to examine for evidence of a fungal infection.

(u) B. A Gram stain would be used for a bacterial infection and would be inappropriate in this situation.

(c) C. The history and exam is consistent with a scabies infection. Scrapings from the burrows should be examined for the presence of mites, eggs, and feces.

(u) D. A Tzanck prep would be used to examine for giant multinucleated cells characteristic of a herpes infec

. Diagnostic Studies/Dermatology

A 26 year-old presents with two days of a generalized, non-pruritic rash with concurrent low grade fever and sore throat. He is otherwise in good health with no history of dermatologic problems other than

acne and a non-painful ulceration at the base of his penis seven months ago that resolved spontaneously. Examination reveals a macular- papular rash spread diffusely over the body including the palms and soles of the feet. Shallow ulcers are noted on the buccal mucosa while the pharynx is moderately erythematous. Which of the following is the most appropriate initial diagnostic study?

A. Tzanck smear of lesion

B. Serum FTA-Absorption test

C. Streptococcus pyogenes culture

D. Epstein-Barr IgM titer Explanations

(u) A. A Tzanck smear is commonly used for diagnosing herpes virus infections.

(c) B. With secondary syphilis, 100% of persons test positive with serum FTA-Absorption test.

(u) C. Though some attributes of the case point to a scarlatina- like rash the prior genital lesion and palmar involvement make this less likely.

(u) D. Epstein-Barr IgM titer is used in the diagnosis of infections such as mononucleosis which would generally not present with this type of rash unless a penicillin had been given to the patient.


A 34 year-old female presents with complaints of a skin rash associated with a low-grade fever, malaise and anorexia. She denies any pruritis. Physical examination reveals the presence of a diffuse maculopapular rash involving the palms and soles associated with generalized lymphadenopathy. Which of the following will confirm the suspected diagnosis?

A. VDRL

B. patch testing

C. acetowhitening

D. Gram stain and culture Explanations

(c) A. This patient most likely has secondary syphilis. Serological tests, like the VDRL, are usually positive during this stage with high titers.

(u) B. Patch testing is utilized to identify a causative agent and confirm a diagnosis of allergic contact dermatitis.

(u) C. Acetowhitening helps in the detection of subclinical penile or vulvar warts.

(u) D. Gram stain and culture should be performed on lesions suspected to have a bacterial origin.


A 35 year-old female who recently returned from a backpacking trip complains of fatigue, malaise, fever, chills, and arthralgias. Physical examination reveals a 6 cm annular lesion with a red border and a clear center on her mid-back. Which of the following laboratory tests would support your diagnosis?

Answers

A. KOH prep of skin scrapings B. Blood cultures

C. RAST testing

D. Serologic antibody testing Explanations

(u) A. Although the skin lesion may resemble a fungal infection, a fungal dermatophyte would not present with systemic symptoms.

(u) B. Culturing of <i>Borrelia burgdorferi</i> from clinical specimens, with the exception of skin biopsies at the site of the lesion, have resulted in low yields.

(u) C. RAST testing is utilized in evaluation of allergies and is not indicated in this situation. (c) D. Most people with Lyme Disease will have a positive serologic test after the first few weeks of infection and this would support the diagnosis.


A 37 year-old right-handed landscaper comes to the office for evaluation of recurrent itching and stinging of the skin on his right hand. Physical examination reveals confluent papules, vesicles, erosions and crusts on the dorsum of his right hand. Which of the following is the most appropriate initial diagnostic study in this patient?

A. Skin scraping and microscopy

B. Patch testing

C. RAST testing

D. Skin biopsy Explanations

(u) A. Skin scraping and microscopy are used to identify the organism, ova or feces in the laboratory diagnosis of scabies. (c) B. In patch testing, substances are applied to the skin in shallow cups and left in place for 24-48 hours.

(u) C. Sensitivity to an allergen is confirmed by a papular vesicular reaction that occurs within 48-72 hours of the laboratory testing. RAST testing is more specific and would not be done as the initial diagnostic study in this patient. (u) D. A skin biopsy is indicated for all skin lesions that are suspected to be neoplasms.


A 58 year-old female comes to the office because she noticed a white spot on her tongue. She has a 42 pack/year smoking history. On examination, she has an 8 mm white thickened, keratinized lesion on the ventral tongue. The lesion cannot be removed by rubbing the mucosal surface. Which of the following studies is most appropriate to confirm the suspected diagnosis?

A. Incisional biopsy

B. Tzanck smear

C. Gram stain

D. Potassium hydroxide wet prep Explanations

(c) A. Leukoplakia is characterized as a white plaque that cannot be removed by wiping the mucosal surface. Tobacco use is strongly associated with an increased incidence of leukoplakia and oral cancer. An incisional biopsy of the lesion is required for histologic evaluation of the tissue.

(u) B. Herpes simplex is a viral infection caused by the herpes simplex virus (HSV) group. Vesicles may be visualized on the soft palate, floor of mouth, and tongue. A Tzanck smear is taken from a vesicular lesion and stained for identification of herpes simplex. (u) C. A direct gram stain of a scraping/swab from oral cavity is performed on lesions due to suspected bacterial or yeast infections.

(u) D. Oral candidiasis is characterized by creamy curd-like patches that can be easily rubbed off the mucosal surface. The diagnosis can be confirmed by wet preparation using potassium hydroxide which reveals pseudohyphae and yeast forms.


An 8 year-old child is brought in by his mother with a two day history of spreading, non-pruritic red rash. The rash was preceded by moderate fever, sore throat and rhinorrhea. Examination reveals a moderately ill appearing child with a fine, macular-papular rash on an erythematous base spread diffusely over the trunk with some accentuation in the skin folds. The face is flush with perioral pallor. There is palpable anterior cervical lymphadenopathy. Which of the following is the most appropriate diagnostic study to establish the diagnosis?

A. Shave biopsy

B. Epstein-Barr virus Ig G

C. Complete blood count

D. Throat culture Explanations

(u) A. Disorders such as erythema multiforme (EM) minor favors the extremities while the EM major may favor the trunk and have associated oral mucosa involvement but generally has blistering lesions. Direct immunofluorescence studies are negative in these disorders.

(u) B. Epstein-Barr virus Ig G would not be helpful in that it screens for prior exposure to this virus or illness such as mononucleosis.

(u) C. Though a complete blood count is commonly ordered and may be helpful in stratifying illness in this case it would not be diagnostic as to the etiology.

(c) D. Scarlatina rash is due to infection with group A strep. A throat culture would be the most appropriate diagnostic study to establish the diagnosis in this patient.


A patient is concerned about being exposed to condyloma acuminata. Which of the following tests is most appropriate to perform in order to better identify these lesions?

A. Acetowhitening

B. Tzanck smear

C. Potassium hydroxide test

D. Wood's light fluoroscopy Explanations

(c) A. Acetowhitening is used to facilitate the diagnosis of condyloma acuminata lesions. A 3 to 5% acetic acid solution is applied to these suspected genital warts for five to ten minutes. Condyloma lesions will whiten and appear as circumscribed macular or papular lesions with a granular surface.

(u) B. Tzanck smears are used in making the diagnosis of herpetic lesions, such as herpes simplex, varicella, and herpes zoster infection.

(u) C. Potassium hydroxide tests are used to rule out the presence of dermatophyte (fungal and yeast) infections.

(u) D. Wood's light fluoroscopy is used in the assessment of dermatophyte infection and a bacterial infection known as erythrasma.


A positive Wood's light examination (fluorescence) demonstrates A. viral infection with herpes zoster.

B. bacterial infection with Treponema pallidum.

C. parasitic infestation with Pediculus humanus.

D. mycotic infection with Microsporum canis. Explanations

(u) A. Lesions of herpes, Treponema, and Pediculus infections do not fluoresce.

(u) B. See A for explanation.

(u) C. See A for explanation.

(c) D. Microsporum causes tinea capitis and fluoresces blue-green under Wood's light.

Health Maintenance/Dermatology

A 9 year-old boy comes to the office with his mother to discuss treatment for chronic dry skin, and pruritic inflammatory lesions of the flexor surfaces of the neck, hands and wrists. Past medical history is significant for allergic rhinitis in the spring and fall. On physical examination the skin lesions are excoriated, and lichenified with crusted patches. Which of the following prevention strategies can help minimize the symptoms in this patient?

A. Avoid rubbing or scratching

B. Limit sun exposure

C. Take hot baths

D. Consume hot liquids Explanations

(c) A. Rubbing or scratching plaques can exacerbate the pruritis and lichenification in atopic dermatitis. (u) B. UVA- UVB phototherapy is an effective treatment for atopic dermatitis. (u) C. Hot baths can exacerbate the pruritis in atopic dermatitis. Tepid baths followed by use of unscented emollient creams can help prevent itching and scratching.

(u) D. In rosacea, the facial flushing and increased skin temperature often occurs in response to the stimulation of hot liquids in the mouth.


According to the Advisory Committee on Immunization Practices, which of the following is the recommended age range for the first or initial MMR (measles, mumps and rubella) vaccination?

A. 2-4 months

B. 12-15 months

C. 4-6 years

D. 11-12 year Explanations

(h) A. MMR vaccination is not approved for use in infants below the age of 12 months. (c) B. The recommended age range for the initial vaccination against MMR is 12-15 months.

(u) C. The second dose of the MMR vaccine is routinely recommended to be administered between 4-6 years of age.

(u) D. Any child not previously vaccinated by 11-12 years of age may receive the vaccine. This is considered to be a "catch- up" immunization and is not the recommended age range for the initial vaccination.


A person with atopic dermatitis should be advised to Answers

A. avoid cutaneous irritants.

B. take hot water baths or showers.

C. use a high potency glucocorticoid on skin after bathing. D. begin a prophylactic antibiotic. Explanations

(c) A. Avoidance of cutaneous irritants, such as wool and other rough clothing, is the cornerstone of therapy for atopic dermatitis.

(u) B. Patients should bathe in warm, tepid water, not hot water.

(u) C. Topical glucocorticoids of low or medium potency in a cream or ointment base should be used on the skin immediately after bathing.

(u) D. Prophylactic antibiotics are not indicated in the treatment of atopic dermatitis.


Which of the following is considered a risk factor for the development of malignant melanoma?

A. male gender

B. inability to tan

C. Japanese ethnicity

D. brown-haired individuals Explanations

(u) A. Incidence of malignant melanoma is equal in males and females.

(c) B. Inability to tan and propensity to burn are risk factors for developing malignant melanoma.

(u) C. Malignant melanomas are most common in Caucasians and are rarely seen in the Japanese population.

(u) D. Red hair and freckling is one of the major risk factors for malignant melanoma, not brown hair.


Which of the following patients is at highest risk for the development of the skin disorder known as erythrasma? A. Lactating women

B. Postmenopausal women

C. Seniors living in cold northern climate

D. People living in tropical climate Explanations

(u) A. Lactating women are at increased risk for staph infections in the breast.

(u) B. Postmenopausal women are at increased risk for atrophic vaginitis but not for erythrasma.

(u) C. Seniors living in cold conditions are at risk for winter itch which is worse with dry heat.

(c) D. People living in warm, tropical climate, people wearing occlusive clothing or shoes, obese patients, and those with hyperhidrosis are at increased risk for erythrasma. The diagnosis of this condition is made by demonstration of a coral red fluorescence.

Health Maintenance/Dermatology Zostavax (varicella-zoster vaccine) is contraindicated in which of the following groups of patients?

A. Chemotherapy patients

B. Adults over 60 years of age

C. Patients allergic to eggs

D. Patients who have recovered from shingles Explanations

(c) A. Zostavax is a live attenuated vaccine and is contraindicated in patients with immunodeficiency states, malignancy affecting the bone marrow, pregnant women, and patients taking immunosuppressive medications.

(u) B. A single dose of zoster vaccine is recommended for patients over the age of sixty without other contraindications.

(u) C. Patients with an anaphylactic reaction to gelatin or neomycin should not receive the Zostavax vaccine. However, egg allergy is not a contraindication to the Zostavax vaccine.

(u) D. Patients who have recovered from shingles may still receive the vaccine. This may decrease recurrent varicella zoster and postherpetic neuralgia in these patients.

History&Physical/Dermatology

A 23 year-old male comes to the office with an intensely itchy rash, especially at night for the past week. His roommates have similar symptoms but have not been evaluated. On physical examination, the wrists, web spaces of the hands, and axillae have thin linear markings, tiny vesicles, and excoriations. Which of the following is the most likely diagnosis?

A. Pediculosis

B. Folliculitis

C. Impetigo

D. Scabies Explanations

(u) A. Pediculosis is a lice infection of the scalp, trunk or pubic region. Body louse occurs in persons living in overcrowded residences, and is characterized by intense pruritis with resultant deep excoriation of the neck, shoulders, and upper back. Nits are identifiable on hair shafts.

(u) B. Folliculitis is an infection of the upper hair follicles characterized by itching, burning and pustules in the hairy regions of the body.

(u) C. Impetigo is a contagious infection of the skin caused by staphylococci or streptococci characterized by honey- crusted erythematous erosions of the face or other exposed areas of the body.

(c) D. Scabies is an infestation of the mite Sarcoptes scabiei. It is usually spread by skin-to-skin contact. Scabies is characterized by intense pruritic burrows, vesicles and excoriations of the finger webs, wrist creases and axillae.


A 72 year-old farmer comes to the office for evaluation of a pearly ulcerated papule on his right nostril. The papule has been bleeding off and on for the past couple weeks. Which of the following findings would be most concerning on the physical examination of this patient? A. Cherry angioma

B. T elangiectasia

C. Spider angioma

D. Pyogenic granuloma Explanations

(u) A. A cherry angioma is a common, violaceous vascular lesion usually located on the trunk.

(c) B. Telangiectatic vessels are often visible skin findings with basal cell carcinoma.

(u) C. A spider angioma is a benign red papule with radiating telangiectasia usually located on the face, forearms and hands.

(u) D. A pyogenic granuloma is a solitary vascular nodule that develops rapidly following minor trauma.


A patient presents with a rash, characterized by red macules and edematous papules with a clearing center. This best describes which of the following? Answers

A. erythema marginatum

B. erythema multiforme

C. varicella

D. impetigo Explanations

(u) A. Erythema marginatum is associated with rheumatic fever and is characterized by macular to maculopapular lesions. A clearing center is not found in the rash.

(c) B. Target lesions, also termed iris lesions, are characteristic of erythema multiforme. The rash may be recurrent but typically resolves over 3-6 weeks.

(u) C. The rash of varicella typically has maculopapules, vesicles, and scabs in various stages of development. A clearing center is not found in the rash.

(u) D. The lesions of impetigo are pustules that form a honey-colored crust after rupturing.


Erythema nodosum is characterized by

A. subcutaneous red tender nodules.

B. brown pigmentation on the lower extremities. C. tender lymph nodes in the groin.

D. scaling red macules. Explanations

(c) A. Erythema nodosum produces erythematous red tender nodules, especially on the shins.

(u) B. Brown pigmentation on the lower extremities is a feature of chronic venous insufficiency.

(u) C. Lymphovenereum granuloma is likely to produce tender lymph nodes in the groin as can acute infection in the lower extremities.

(u) D. Scaling red macules are a feature of tinea corporis.


In a patient suspected of having seborrheic dermatitis, the most common site of involvement would be the

10

Answers

A. upper extremities.

B. thighs.

C. scalp.

D. feet. Explanations


(u) B. See C for explanation.

(c) C. The most common site of involvement of seborrheic dermatitis is the scalp. Other common sites include the eyebrows, eyelids, nasolabial fold, and ears.



In a patient with dyshidrotic eczema on which area of the body would associated vesicles be found?

A. Axillae

B. Intertriginous areas

C. Palms

D. Upper back Explanations


(u) B. See C for explanation.

(c) C. Vesicles associated with dyshidrotic eczema are most commonly found on the palms with the dorsum of the hands spared. The soles may also be affected in a similar fashion.



In which of the following patients would one most likely find acanthosis nigricans?

A. A 55 year-old obese female with hyperinsulinemia

B. A 55 year-old male with an enlarged spleen and pancytopenia

C. A 24 year-old female with increased Lyme titers

D. A 60 year-old male with increased triglycerides Explanations

(c) A. Acanthosis nigricans is associated with patients who have hyperinsulinemia.

(u) B. Hairy cell leukemia is associated with an enlarged spleen and pancytopenia. Acanthosis nigricans is not a

cutaneous manifestation.

(u) C. Erythema chronicum migrans is the characteristic lesion associated with Lyme disease.

(u) D. Eruptive xanthelasma is associated with increased triglycerides.


The bite from which of the following is associated with fever, lacrimation, rhinorrhea, bradycardia, hypertension, and tachyarrhythmias?

A. Brown recluse spider

B. Black widow spider

C. Black flies

D. Bedbugs Explanations

(u) A. Brown recluse spider bites may cause reactions ranging from mild urticaria to full thickness necrosis but typically, there are no systemic symptoms.

(c) B. Black widow spider bites can inject venom that contains a neurotoxin which can produce reactions at the site of the bite along with varying degrees of systemic symptoms.

(u) C. Black fly bites produce local reactions as well as fever, nausea, and general lymphadenopathy.

(u) D. Bedbugs have nocturnal feedings that produce a linear arrangement of papular urticaria. There are no systemic symptoms associated with their bites.


What is the most common examination finding in a patient diagnosed with mumps?

A. Occipital lymph node swelling

B. Parotid gland tenderness

C. Splenic enlargement

D. Testicular tenderness Explanations

(u) A. Lymph node swelling can occur secondary to facial edema but can be variable and more often involves the submandibular and cervical lymph node chains.

(c) B. Parotid gland tenderness and swelling are the hallmark findings of mumps.

(u) C. Splenic enlargement is not a common exam finding even in extra- salivary disease.

(u) D. Testicular tenderness can occur in as many as 40% of post-pubescent men but it is not the most common finding considering all cases of mumps.


Which of the following is the only disease that forms an ulcer at the site of inoculation?

A. Tularemia

B. Scabies

C. Lyme disease

D. Rocky Mountain Spotted Fever Explanations

(c) A. Tularemia is an acute infection that is transmitted by handling the flesh of infected animals, by the bites of insect vectors and by inoculation of conjunctiva.

(u) B. Scabies is caused by the infestation of a mite and is associated with significant pruritus. There may be minimal cutaneous findings although a burrow and skin tracks may be seen early in the course of this disease.

(u) C. Lyme disease is associated with a rash known as erythema chronicum migrans. The rash has an expanding border and central clearing.

(u) D. Systemic symptoms predominate with Rocky Mountain Spotted Fever and the rash has an acral distribution pattern that may occur on the palms and soles. It does not have any ulcer associated with it.


Which of the following lesions is most characteristic of psoriasis?

A. hypopigmented macules on hands and forearms

B. pruritic pustules on finger webs and wrist creases C. crusting vesicles around the mouth and face

D. scaling plaques on knees and elbows Explanations

(u) A. Hypopigmented macules are more characteristic of vitiligo. (u) B. Pruritic pustules are more characteristic of scabies.

(u) C. Crusting vesicles around the mouth and face are more characteristic of herpes or impetigo.

(c) D. Psoriasis most commonly presents with scaling plaques and papules on the scalp, elbows, forearms, lumbosacral regions, knees, hands, and feet.


Which of the following skin rashes is pathognomonic of rheumatic fever?

A. erythema marginatum

B. erythema nodosum

C. diffuse petechiae

D. purulent bullae Explanations

(c) A. Erythema marginatum is one of the major Jones criteria for the diagnosis of acute rheumatic fever. (u) B. Erythema nodosum lesions are associated with many diverse causes including various infections, malignancies, drug sensitivities and inflammatory/granulomatous diseases.

(u) C. Diffuse petechiae are most commonly seen in conditions that cause thrombocytopenia.

(u) D. Purulent bullae are noted in patients with scalded-skin syndrome.

Scientific Concepts/Dermatology

A 66 year-old woman with type 2 diabetes comes to the office because she has had a painful red patch that has been spreading on her right lower leg over the past 3 days. Her temperature is 100.4 degrees F. Physical examination of her right lower leg reveals a 3 cm tender, warm, erythematous, and edematous plaque. Which of the following pathogens is most likely causing this patient's symptoms?

A. Staphylococcus aureus

B. Haemophilus influenzae

C. Proteus mirabilis

D. Escherchia coli Explanations

(c) A. S. aureus and group A beta-hemolytic streptococci are the most common causes of cellulitis.

(u) B. Haemophilus influenzae can cause facial cellulitis in young children.

(u) C. Proteus can be one of the pathogens that cause infectious gangrene.

(u) D. Escherchia coli can cause crepitant cellulitis. It would not be the most common cause of cellulitis in this

patient.


Which of the following is characterized by epidermal hyperplasia and an increase in the epidermal turnover?


B. Tinea corporis

C. Ecthyma

D. Psoriasis Explanations

(u) A. Inflammation in atopic dermatitis results in lichenification of the skin from itching, which leaves the skin dry and scaly when it resolves. The inflammation is the result of elevated T-lymphocyte activation, defective cell- mediated immunity, and IgE overproduction. Epidermal hyperplasia is not involved in atopic dermatitis.

(u) B. Tinea corporis is a fungal infection and does not have epidermal hyperplasia.

(u) C. Ecythma is the result of an infection from group A beta-hemolytic streptococcus and contaminated with staphylococci. Like atopic dermatitis and tinea corporis, ecthyma has no epidermal hyperplasia.

(c) D. Psoriasis is characterized by an increased epidermal cell turnover, increased numbers of epidermal stem cells, and an abnormal differentiation of keratin. This leads to the classic scale associated with psoriasis.


Which of the following is characterized by epidermal hyperplasia and an increase in the epidermal turnover? Answers


B. Tinea corporis

C. Ecthyma

D. Psoriasis Explanations

(u) A. Inflammation in atopic dermatitis results in lichenification of the skin from itching, which leaves the skin dry and scaly when it resolves. The inflammation is the result of elevated T- lymphocyte activation, defective cell-mediated immunity, and IgE overproduction. Epidermal hyperplasia is not involved in atopic dermatitis.

(u) B. Tinea corporis is a fungal infection and is does not have epidermal hyperplasia.

(u) C. Erythema is the result of an infection from group A beta- hemolytic streptococcus and contaminated with staphylococci. Like atopic dermatitis and tinea corporis, ecthyma has no epidermal hyperplasia.

(c) D. Psoriasis is characterized by an increased epidermal cell turnover, increased numbers of epidermal stem cells, and an abnormal differentiation of keratin . This leads to the classic scale associated with psoriasis.


Which of the following is the most common type of skin cancer?

A. basal cell

B. melanoma

C. atypical nevi

D. squamous cell Explanations

(c) A. Basal cell cancer is the most common cause of skin cancer usually occurring on sun-exposed areas.

(u) B. While malignant melanoma is the leading cause of death from skin disease, it is not the most common skin cancer.

(u) C. Atypical nevi are associated with melanoma. They are diagnosed clinically, not histologically. Any atypical nevi suspected to be melanomas should be removed.

(u) D. Squamous cell carcinomas also occurs in sun-exposed areas, but are less frequent than basal cell cancers.


Which of the following mediators is responsible for initiating the urticaric response? A.Cyclic AMP

B. Prostaglandins

C. Prednisone

D. IgE Explanations

(u) A. Increased levels of Cyclic AMP inhibit the histamine response.

(u) B. Prostaglandins inhibit the release of histamine.

(u) C. Prednisone is used to treat urticaria. (c) D. IgE triggers the release of histamine from mast cells that leads to urticaria.


Which of the following types of infection is most likely to benefit from hyperbaric oxygen therapy?

A. Clostridial infection

B. Group A beta hemolytic streptococcus

C. Serratia marcescens

D. Methicillin resistant Staphylococcus aureus Explanations

(c) A. Patients with clostridium myonecrosis (gas gangrene) will benefit from hyperbaric oxygen therapy, penicillin therapy, and radical surgical excision.

(u) B. Patients with group A beta hemolytic strep, staph aureus, and community acquired methicillin resistant staph aureus will benefit from antibiotic therapy but these organisms are not anaerobic so hyperbaric oxygen therapy is not useful.

(u) C. See B for explanation.

(u) D. See B for explanation.

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