Erythema Multiforme

Clinical Description

Acute, inflammatory reaction which manifests with papular lesions which are classically multicolored. These lesions are described as typical targets. The majority of cases are caused by herpes simplex but bacteria, fungi and occasionally drugs may induce EM.

Signs and Symptoms

• The classic lesion is a target lesion found on the distal extremities and palms with relative sparing of the trunk.
• Usually asymptomatic but may be painful
• Spares mucosa in mild disease (erythema multiforme minor) but severe disease may involve mucosa (erythema multiforme major)

Investigations

• Usually a clinical diagnosis. Tzanck smear maybe done

Treatment

• Identify the cause and treat. If the cause is medicine, stop the medicine
• Acyclovir 400mg P.O 8 hourly for 7 to 10 days for all cases as herpes simplex is most common cause.
• Short course of cortico-steroids e.g., Prednisolone 1mg/kg for 3-5 days of severe with painful mucosal erosions

Recurrence

• Give suppressive Acyclovir 400 mg 12 hourly for 2 to 3 days