Purpura fulminans as a sequel to erythema nodosum in a child with homozygous Leiden mutation and acquired protein S deficiency

A 6-y-old boy presented with generalized, bruise-like swelling of both legs. Three weeks later, he developed purpura fulminans in one of the affected feet. Histology of the leg swelling was in accordance with erythema nodosum. The boy proved to be homozygous for the Factor V Leiden mutation and to have acquired protein S deficiency. He recovered, with partial loss of two toes. CONCLUSION: In contrast to what is often stated, erythema nodosum is not always a benign condition. On the basis of this report, we suggest that if extensive erythema nodosum develops in an individual without any known thrombophilic disorder, investigations with respect to the latter should be performed.