Bacterial Skin Infection

Bacterial skin Infection 

University of Hargeisa Medical Faculty (UoH-MF)

Dermatology Department Dr. Ismail Adam Abdilahi 2008

Predisposing factors Trauma

or abrasion of the skin Viral disease . Primary dermatoses e.g. Eczema . Poor hygiene and overcrowding

Staph. infections Impetigo Boils

.

contagiosum .

Impetigo contagiosum Definition

:

 Acute

contagious superficial pyogenic infection of the skin.

Types

:

 Non-bullous  bullous

Non-bullous impetigo Caused

by staph. in association with strep. or by strep alone.

Clinical

features:

Age

: mainly preschool Sites : face,limbs and scalp are common. Palms

and soles are not affected.

There

is thin-walled vesicles on erythematous base that soon rupture→ yellowish brown crusts that dry and separate → erythema which fades without scarring. Complication : post-strep. acute glomerulonephritis .

Bullous impetigo Caused

by staph through staph toxin (exfoliatin)

Clinical Age

features:

: all ages Site : face is often affected but may occur any where including palms and soles.

The

bullae are less rapidly ruptured( persistent for 2-3 days) and become much larger. When rupture →thin brownish crust.

Treatment of impetigo Use

antiseptic e.g. potassium permanganates. Topical antibiotic . Systemic antibiotics . Treatment of predisposing factors: e.g. Scabies.

Boils Painful

erythematous tender papular lesions which are related to infection of hair follicles . Sites: neck, axillae, buttocks, and thighs.

If

infection spreads to involve several follicles→ carbuncle. Screen for diabetes mellitus in case of recurrent boils.

Treatment Is

of boils:

similar to that of impetigo but systemic antibiotics are often necessary. Surgical incision may be needed.

Streptococcal infections Erysipelas. Ecthyma.

Erysipelas Widespread

erythema and cellulitis due to infection of the dermis and upper cutaneous tissue by group A strep reaching the dermis through a wound or a small abrasion→ red, swollen and tender skin

Lymphangitis

and lymphadenitis are frequent. Common sites are legs and face. Complications:

lymphedema, subcutaneous abscess, septicemia, nephritis and meningitis.

Treatment Penicillin

:

1 g/day or Erythromycin . Treatment of any underlying skin disease e.g. chronic fissuring.

Ecthyma  Chronic

ulceration due to infection of the dermis by staph and strep.  Often prolonged so needs intensive local antiseptic treatment combined with systemic antibiotics.

Mycobacterial infections -Cutaneous tuberculosis . -Leprosy .

Cutaneous tuberculosis

Lupus vulgaris Most

common form of skin tuberculosis.

Infection through

hematogenous spread or primary inoculation of the skin with mycobacterium tuberculosis.

Histopathology

: granulomas with central caseation and the organism can be demonstrated.

Clinical

features:

Erythema,

scaling and scarring plaques.

Treatment

: multi-drug

therapy for 6-9 months : Rifampicin 600mg daily (450mg for body wt less than 55kg) INH 300mg daily Both half an hour before breakfast for 6 month Pyrazinamide

months only

1.5-2gm daily for 2

TREATMENT OF LEPROSY PAUCIBACILLARY

: for

6 month . Rifampicin 600 mg monthly Dapsone 100 mg daily .

MULTIBACILLARY for 2 years . Rifampicin 600 mg + clofazimin 300 mg monthly . Dapsone 100 mg + clofazimin 50 mg daily .

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