Erythema nodosum - Erythematous lesions

Erythema nodosum

Definition

Erythema nodosum is an immunemediated disorder resulting in red tender pretibial subcutaneous nodules.

Incidence

1–5 per 100,000 per year.

Age

Peak incidence 15–40 years.

Sex

F > M

Aetiology

Streptococcal pharyngitis is the most common associated condition.

Many cases are idiopathic but this is a diagnosis of exclusion.

Drugs: Penicillin, oral contraceptive pill. Pregnancy.

Conditions with hilar lymphadenopathy: Sarcoidosis, tuberculosis, coccidioidomycosis, histoplasmosis, Hodgkin’s lymphoma and Chlamydophila pneumoniae.

Gastrointestinal disorders: Inflammatory bowel disease, Behc¸et’sˆ syndrome and bacterial gastroenteri-tides.

Clinical features

Painful bluishred nodules up to 5 cm in diameter appear in crops over 2 weeks on the anterior surface of both lower legs. They slowly fade leaving bruising and scarring of skin. Malaise, fever and arthralgia may accompany the rash.

Management

Symptomatic treatment and management of any underlying cause is essential. Recovery may take weeks, and there may be recurrence.