Introduction
Impetigo contagiosa is a superficial, highly contagious, bullous skin disorder caused by coagulase positive staphylococci and occasionally -haemolytic streptococci.
Symptoms and Clinical features of impetigo contagiosa
Children are more commonly affected
- Initial lesions are superficial vesicles, or bullae found around orifices: eyes, nose and ears
- Begins with a 2 mm erythematous macules which quickly develop into vesicles or bullae
- Blisters are superficial and rupture easily, releasing a thin straw-coloured seropurulent discharge
- The exudate dries to form loosely stratified golden yellow crusts
- Auto-inoculation from fluid (from ruptured blister) leads to multiple lesions
- As the lesions spread peripherally and the skin clears centrally, large circles are formed by fusion of the spreading lesions to produce gyrate patterns
- Lesions heal without scarring, but may leave behind erythema and hyperpigmentation
- Other pruritic dermatoses may become impetiginized (i.e. infected with the above organisms):
- Scabies
- PediculosiPapular urticaria
- Atopic eczema
Differential diagnoses
- Ringworm
- Ecthyma
- Herpes simplex
Complications of impetigo contagiosa
- Regional lymphadenopathy
- Cellulitis
- Rarely: septicaemia
- Rarely: acute glomerulonephritis, if
nephritogenic strain of streptococcoci is involved
Investigations
- Wound swab for bacteriology and sensitivity
Treatment
Treatment objectives
- Treat infection
- Treat underlying pruritic dermatoses
- Prevent complications
Non-drug treatment
- Debride crusted lesions with soap and water or desloughing antibacterial agents
- Dry weepy lesions with astringent such as potassium permanganate, sodium chloride 0.9% solution, hydrogen perioxide
Drug treatment
Erythromycin
Adult and child over 8 years:
- 250-500 mg orally every 6 hours or 500 mg – 1 g every 12 hours for 5-10 days
Child:
- up to 2 years: 125 mg orally
every 6 hours; - 2 – 8 years: 250 mg every 6 hours
Or:
Co-trimoxazole
Adult:
- 960 mg orally every 12 hours for 5-10 days
Child:
- 6 weeks – 5 months: 120 mg;
- 6 months -5 years: 240 mg;
- 6-12 years: 480 mg taken orally every 12 hours for 5-10 days
Supportive measures
- Debride crusted lesions: Dislodging
antibacterial agen - Avoid auto-inoculation e.g. with fingers, shaving brushes,
handkerchiefs, or pillow cases - Strict personal hygiene
- Treat underlying skin disease(s)
Notable adverse drug reactions
- Sulphonamide and co-trimoxazole: fixed drug eruption