“reactive” and idiopathic skin diseases rich callahan mspa, pa-c fletcher allen dermatology...
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“Reactive” and Idiopathic Skin Diseases
Rich Callahan MSPA, PA-C
Fletcher Allen Dermatology
Burlington, Vermont
ICM I – Summer 2009
Overview
• Erythema Multiforme (EM)• Erythema Nodosum (EN)• Stevens-Johnson Syndrome/Toxic
Epidermal Necrolysis (TEN)• Urticaria/Angioedema• Lichen Simplex Chronicus/Prurigo
Nodularis• Lichen Planus
EM – What is it?
• An acute, common skin rash associated with a number of causative factors, although 50% of the time a precipitating cause is not found.
• Classified as a reactive, inflammatory process of the skin, or “Hypersensitivity syndrome.”
• Reactive change in dermal vasculature with overlying epidermal changes
EM – Epidemiology/Causative Factors
• Can be caused by drugs, infections (Herpes,) pregnancy, internal malignancy, acute URI, atypical pneumonia
• ~50% idiopathic• Mostly see in younger patients, most
common age range is 20-40 years• I have seen several patients who develop
EM after HSV outbreaks (cold sores)
EM – Clinical Presentation
• Characteristic erythematous, target-shaped, urticarial papules, vesicles and bullae
• Affects trunk, extremities, mucous membranes, palms/soles.
• Lesions appear quickly in a symmetric pattern, usually first on dorsal hands/feet, then migrating along extensor extremities, then to trunk in severe cases.
• Can be asymptomatic, pruritic or painful.• Occassionally, will manifest only as oral bullae and
ulcerations.
EM – Clinical Presentation
• Eruption evolves over several days, may be preceded by prodromal symptoms including malaise, fever or burning/itching at sites where EM will later develop.
• Presentation can be entirely non-diagnostic at first, then later dx’ed as EM when classic “target lesions” develop.
• Entire course of disease usually 1 month or less. • Rarely life-threatening with extensive mucous
membrane involvement, patches of vesiculation, etc
EM - Diagnosis
• EM is a clinical diagnosis based on patient history and disease presentation.
• Skin biopsy seldom helpful in my experience as histologic findings can be non-specific at early stages of disease, which is when it tends to get biopsied.
• Biopsy of target lesions generally diagnostic, but seldom biopsied as is an easy clinical diagnosis by that point!
EM - Treatment
• Mild cases do not require treatment.• Moderate cases respond well to a 1-3 week
course of oral steroids (prednisone.)• Severe cases treated with IV steroids.• In recurrent cases with positive HSV
association, I have used prophylactic therapy with oral antiviral meds (Valtrex) with good success.
Erythema Nodosum – EN – What is it?
• An acute panniculitis of the lower extremities with diverse causes
• Considered a delayed hypersensitivity reaction to a number of possible antigens, I.e., it is a reaction to a concurrent disease or condition.
• Most common cause today is streptococcal infection.
• Can be precipitated by drugs, infections, sarcoidosis, misc. inflammatory disorders
EN - Causes
• Infections• Bacterial• Fungal• Viral• GI parasites• Drugs (esp. OCP’s)
• Cancer• Concomitant Disease• Sarcoidosis• IBD• Ulcerative Colitis• Crohn’s Disease
EN - Epidemiology
• Women >> men. Female: Male ratio is 5:1
• Peak ages of incidence are 18 – 35 years.
• Extremely rare in the elderly.
• Historically, much less common in the modern area with advent of antibiotic drugs.
EN – Clinical Presentation
• Presents as development of painful red nodules, patches and plaques, usually on lower legs, over a period of 1-2 weeks.
• Often preceded by prodromal symptoms of fever, malaise, arthritis and arthralgias.
• Individual lesions begin as reddish, swollen papules on shins bilaterally, then grow into violaceous, indurated, tender patches and plaques which resolve in 1-2 weeks.
• Eruption can recur in crops for months to years.
EN - Treatment
• Usually resolves spontaneously w/o treatment.
• Symptomatic relief with rest and/or NSAID’s.
• SSKI (supersaturated potassium iodide.)• Prednisone• ID and treatment of precipitating cause if
possible.
Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis – What is it?
• Both names represent a spectrum of disease with SJS being the less severe end.
• A life-threatening condition characterized by large scale and widespread necrosis and detachment of epidermis, affecting both skin and mucosal surfaces of eyes (conjunctivae,) nares, mouth, anorectal/genital areas.
• One of the few truly acute medical emergencies in Dermatology.
SJS/TEN
• Pathophysiology not entirely understood, but thought to be reaction in keratinocytes where cells accumulate foreign antigen and are stimulated to apoptosis (cell death) by T-cells.
• Large areas of epidermis become necrotic and slough off in sheets
• Results in massive transcutaneous water loss and usually secondary bacterial infection
SJS/TEN - Causes
• Most often caused by drugs, then infections, then rarely by a malignancy.
• Drugs include: Sulfonamides, Bactrim/Septra, Quinolones, Cephalosporins, acetaminophen, phenobarbital, NSAID’s, cocaine, ginseng, allopurinol, fluconazole, many others.
• Infections include influenza, HSV, Epstein-Barr virus, Cat-Scratch disease, histoplasmosis
• Malignancies include carcinomas and lymphomas
SJS/TEN Spectrum of Disease
• Grade I - SJS: Less than 10% of Body Surface Area (BSA) affected.
• Grade II - SJS/TEN Overlap: Between 10% and 30% BSA affected.
• Grade III – TEN: Greater than 30% BSA affected.
SJS/TEN Epidemiology/Morbidity/Mortality
• Usually seen in Caucasians, male:female ration is 2:1.
• Average patient is 20-40 years old, although occasionally seen in infants/elderly.
• If BSA involvement 10% or less, mortality is 1-5% of cases. 30% or higher BSA involvement has mortality rate between 25% and 35%
• Overall mortality for entire SJS/TEN spectrum of disease is 15%
SJS/TEN – Clinical Presentation
• Clinically manifests as erythematous and purpuric macules and target lesions, distributed over trunk, palms, soles and mucosal areas. Blister formation and sloughing/necrosis of skin follow.
• Nikolsky Sign: Pushing down on blisters causes them to spread laterally with little resistance
• Skin rash preceded by cough/URI symptoms. • Patients have fever, electrolyte imbalances,
eye/mucous membrane involvement, pain, occassional lung involvement.
SJS/TEN – Clinical Presentation
• Mucosal lesions lead to widespread epidermal sloughing and crust formation.
• Extensive disease can lead to scarring, stricture formation and partial loss of funcion of organ system involved.
• Eye involvement includes corneal ulcerations and conjunctival injury which can lead to scarring and blindness.
SJS/TEN - Treatment• Most often a reaction to drugs, so look for
offending cause in all cases: Usually the newest drug on a patient’s list, within 1 to 4 weeks of starting it
• Treatments are supportive, although oral prednisone is often used in an attempt to shorten duration of illness.
• Other treatments include oral antihistamines, lidocaine gargles, liquid/soft diet, Burrow’s compresses, topical steroids to non-eroded areas, ophthalmology consult, antibacterial therapy for secondary infections.
Urticaria/Angioedema
• Urticaria presents as groups of itchy, pink/flesh-colored wheals
• Caused by edema, or fluid accumulation in epidermis/superficial dermis
• Papillary vascular plexus
• Angioedema presents as broad, poorly-defined areas of swelling
• Caused by edema of dermis and subcutis
• Deep vascular plexus
Urticaria/Angioedema
• Wide Variety of Causes:
• 50-60% of cases idiopathic
• Allergies• Drugs• Contact urticaria• Autoimmune and
immunologic mediated
• Physical Urticaria – Angioedema
• Infections• Treatment usually
with antihistamines and/or prednisone
LSC/Prurigo Nodularis
• Lichenification of skin in direct reaction to repeated rubbing and scratching of skin
• Skin becomes thickened with accentuation of skin markings
• Scratching becomes pleasurable to patient
• Dome-shaped, hyperpigmented papules and nodules in areas of lichenification
• Often deeply excoriated
• Hyperplasia of cutaneous nerves leads to enhanced sensitivity and pruritis
Lichen Planus (LP)
• Idiopathic eruption defined by the 4 P’s:• Pruritic, purple, polygonal papules• Tends to affect wrists, flexor extremities,
lumbar areas, genitals, mucosa• Tends to last 6 months to one year• Leaves behind deep, long-lasting
hyperpigmentation• Presence of Wickham’s striae diagnostic
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