Erythema elevatum diutinum (EED): a distinctive vasculitis with acute-on-chronic features.

Progress He was investigated thoroughly to exclude an underlying infective process. Repeated full blood counts were normal, C-reactive protein was not elevated and erythrocyte sedimentation rate was 27 mm/hr. Anti-nuclear antibody and human immunodefi ciency virus (HIV) serology was negative. Tumour markers such as carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP) and prostate-specifi c antigen (PSA) were not elevated. A chest radiograph did not reveal any abnormalities. X-rays of the left foot showed chronic osteomyelitis of the second metatarsal (MT) head. Histopathology A skin punch biopsy of the left foot nodule was taken. Histopathology revealed dermal infi ltrates of histiocytes and neutrophils (Fig. 2). There was epidermal acanthosis and parakeratosis. These features were considered to be in keeping with Sweet syndrome and he was started on oral prednisolone 30 mg per day. Six weeks later, he reported minimal improvement. An alternative diagnosis of erythema elevatum diutinum (EED) was considered. On histopathological review, prominent endothelial cell swelling was noted and the neutrophilic infi ltrates were confi rmed to be perivascular rather than diffusely distributed, features less typical of Sweet syndrome and more consistent with EED (Fig. 2). The patient was started on dapsone in August 2012. However shortly after, he was re-admitted with a severe pneumonia and eventually succumbed to sepsis. A review of the lesions while the patient was in the intensive care unit about 5 weeks after dapsone therapy showed a remarkable clearance of the lesions.