bacterial infections of the skin
DESCRIPTION
skinTRANSCRIPT
PRIMARY BACTERIAL INFECTIONS OF THE SKIN
DR. AKRETI SOBTI DEPT OF DERMATOLOGYK. J. SOMAIYA HOSPITAL
INTRODUCTION
Bacterial skin infections – also known as Pyodermas
Mostly superficial
Easy to diagnose and treat
Special investigations not required
Can be treated with topical antibiotics at most times
SKIN AS A BARRIER AGAINST INFECTIONS
CommensalsProtective role against external organismsMostly non-pathogenicRarely pathogenic or opportunisticDepends on immune status of host
pH of skin
Dryness with exfoliationUse of harsh soaps and cleansers remove the normal flora
and cause more harm
APPENDAGESSKIN
SebaceousGlands
BACTERIAL INFECTIONS
SweatGlandsNailsHair
Superficial Deep
Eccrine Apocrine•Sup. Folliculitis•Pseudo-folliculitis•Tri-myco-axillaris
•Furuncle•Carbuncle•Sycosis barbae
AcuteParonychia
Periporitis Hid. Supp.
Acne
Superficial Deep
•Impetigo•SSSS•Pitt. K’lysis•Erythrasma
•Ecthyma•Erysipelas•Cellulitis•Nec. Fascitis
IMPETIGO
Contagious, superficial bacterial infection
Commonly seen in Children
Most favoured sites : Face and extremities
Peri-nasal involvement could be dangerous.
IMPETIGO
2 TYPES OF CLINICAL PRESENTATIONS:Bullous impetigo-
Caused by Staph. aureus. Vesicle enlarge to form bullae
Nonbullous impetigo- Caused by Streptococcus Vesicle rupture to expose red, moist base with crust
formation as lesion expands radially. ‘Honey coloured’ crusting is diagnostic
Bullous impetigo
Non-bullous impetigo
STAPHYLOCOCCAL SCALDED SKIN SYNDROME
Also called “Ritter’s disease”
Staphylococcal epidermolytic toxin syndrome
Follows an episode of sore throat
Caused by lack of immunity to toxins and renal immaturity in children causing poor clearance of toxins
Characterized by peeling of skin after blister formation – similar to burns
STAPHYLOCOCCAL
SCALDED SKIN SYNDROME
STAPHYLOCOCCUS SCALDED SKIN SYNDROME
TREATMENT:
Hospitalization
Intravenous antibiotic therapy
Skin should be lubricated with bland lotions and washed infrequently
ECTHYMA
Characterized by formation of adherent crusts beneath which ulceration occurs
Begins as small pustule on erythematous base which is soon surrounded by a hard crust.
Crust can be removed with difficulty to reveal an irregular ulcer
More common on the legs, thighs and buttocks
Initiated by Group A Beta hemolytic Streptococci and contaminated with Staphylococci.
Ecthyma
CELLULITIS AND ERYSIPELAS
Both are deeper infections of skin
Cellulitis is applied to inflammation of subcutaneous tissue
Erysipelas is infection of dermis and lymphatics
Similar bacteriology – Streptococci and staphylococci
Erythema, heat, swelling and tenderness common in both
CELLULITIS AND ERYSIPELAS
In Erysipelas, edge of lesion is demarcated and raised.
In Cellulitis, diffuse blister formation with hemorrhage
Both can progress to dermal necrosis
Lower extremities and face commonest
Complications – subcutaneous abscess, septicaemia and nephritis(streptococcal)
Erysipelas Cellulitis
FOLLICULITIS
Inflammation of hair follicle
Can be :
Infective - bacterial/viral/fungal
Non infective - grease, oil or post waxing.
Characterized by multiple superficial follicular pustules
Folliculitis
PSEUDOFOLLICULITIS
Not a bacterial infection
Commonly seen in blacks
Results from penetration of sharp tips of shaved hair into the skin
Commonest site is the beard
Characterized by papules and pustules on shaven skin
May cause scarring, keloid formation and hyper pigmentation
PSEUDOFOLLICULITIS
More of a cosmetic problem
Stop shaving for 4-6 wks
Maintain beard hair at 1mm length
Avoid plucking of hair
Topical steroid - antibacterial combination
FURUNCLE
Acute, usually necrotic infection of a hair follicle with S. aureus
Presents initially as a small, follicular inflammatory nodule pustular necrotic
Single or multiple associated with tenderness
Sites involved – face and neck, arms and legs, buttocks and anogenital area
Furunculosis
CARBUNCLE
Deep bacterial infection involving group of furuncles
Most favoured area is nape of neck
Marker for Diabetes mellitus
May require aggressive therapy
Carbuncle
ACUTE PARONYCHIA
Caused by staphylococci
Entry is gained through break in the skin or cuticle as a result of minor trauma
Characterized by acute inflammation with the formation of pus in the nail fold
Treatment is with systemic antibiotics.
Surgical drainage maybe required
PERIPORITIS
Secondary infection of miliaria( the eccrine sweat glands) with staph.aureus
Commonly seen in children
Summer exacerbation
Characterized by multiple erythematous papules and nodules over the forehead face scalp and trunk
Progress to form nontender fluctuant abcess
D/D: furunculosis
ERYTHRASMA
Corynebacterial infection of the skin
Characterized by well demarcated reddish-brown scaly patches on moist body areas such as the axillae or groins.
Most commonly mistaken for Tinea cruris or intertrigo
Differentiated by Wood’s lamp – coral red flourescence
Erythrasma
PITTED KERATOLYSIS
Caused by corynebacterium minutisimum, micrococcus sedantareus & dermatophilus congolensis
Predisposing factors:Excessive sweatingProlonged immersion of hands and feet in waterOcclusive footwearCharacterized by cribriform pattern of fine
punched out depressions on the palms and soles associated with foul smell
TREATMENT
Counseling
Oral antibiotics – erythromycin, azithromycin
Topical antifungal and antibiotic creams
Treatment of hyperhidrosis
TRICHOMYCOSIS AXILLARE
MisnomerCaused by corynebacterium tenuisaxillary and pubic hair become beaded with concretions
(yellow, red or black), made up of tightly packed bacteria
This maybe associated with discoloration of sweat leading to staining of the undergarments and foul smell
Topical antibiotics or shaving will clear the condition
TREATMENT
Topical antibiotics for localized infections
Combination of Oral and Topical therapy for extensive infections.
Topical modalities include Fusidic acid, Mupirocin, Sisomycin, Nadifloxacin, Framycitin-B
Oral antibiotics preferred are Ampicillin, Cloxacillin, Amoxycillin, Cephalosporins or Azithromycin.
Hospitalization, IV antibiotics and /or surgical intervention for deeper infections like Cellulitis and Erysipelas
SECONDARY BACTERIAL INFECTION
Bacterial infection on an underlying conditionScabies / PediculosisEczemasVesiculo-bullous lesionsUlcers