Question:

This 3-year old boy complained of an erythematous vesiculopustular lesion on the face, which spread to the limbs over 2 days. The vesicular lesion rapidly ruptured with yellowish exudate, crusting and scaling on the margin of the lesion. This picture shows the lesion on his arm.

Answer: C. Impetigo

Impetigo is an acute contagious superficial infection of the skin, usually due to Staphylococcus aureus and occasionally Streptococcus pyogenes. It is common in children and is often secondary to minor skin conditions like eczema, insect bites, etc, that predisposes the skin to invasion by the organism. It is contagious in 2 ways, firstly it can spread to other parts of the body and secondly it may spread in the family and in the school.

The lesion starts as a blister which ruptures easily with purulent exudate and honey-coloured crusting. It is polycyclic or circinate and may resemble tinea infection. The affected patient appears relatively well with little systemic upset.

Topical antibiotics including fucidic acid, neomycin or mupirocin may be adequate for localised conditions. Systemic antibiotics are indicated in cases with extensive involvement. Swab for culture should be sent before commencing antibiotics. Antiseptics are useful as an adjunct in removing the crust.