Erythema Nodosum

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ICD-9 Codes

695.2 – Erythema nodosum

Synopsis

Erythema nodosum (EN) represents the most common type of inflammatory panniculitis (inflammation of the fat). It is an inflammatory process, typically symmetrical, and located on the pretibial region. It may be precipitated by endogenous or exogenous stimuli. Streptococcal infections are the most common etiologic factor in children. Sarcoidosis, inflammatory bowel disease, and drugs are more commonly implicated in adults. Most often a cause or trigger is never found. The eruption typically persists for 3–6 weeks and spontaneously regresses without scarring or atrophy.

Upper respiratory tract infection or flu-like symptoms may precede or accompany the development of the eruption. Arthralgias are reported by a majority of patients regardless of the etiology of EN. 

EN can occur at any age, but most cases occur between the ages of 20 and 45, particularly in women. Oral contraceptives are the most common drug association, but EN has been associated with a number of other medications. Pregnancy may also be associated with EN. Bacterial, viral, fungal, and protozoal infections (eg, Streptococcus spp., Shigella, H. capsulatum, HIV, Giardia) may cause EN. In addition to sarcoidosis and inflammatory bowel disease, patients with malignancies, patients undergoing radiation treatment for malignancies, and those with Behçet's syndrome, reactive arthritis, Sweet's syndrome, ulcerative acne conglobata, and Sjögren syndrome may develop EN. Recurrences are sometimes seen, especially with repetition of the precipitating factors.

Löfgren syndrome is a benign variant of sarcoidosis with EN and bilateral enlargement of the hilar lymph nodes. It occurs more commonly in females, especially during pregnancy.

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