Erythema elevatum diutinum with various clinicohistological stages

A 61-year-old man presented with a 3-year history of erythematous firm nodules on the hands and feet. Histopathological findings of the lesional skin revealed perivascular and diffuse neutrophilic infiltrations on the upper and mid-dermis. Increased and dilated blood vessels were observed in the upper dermis. Fibrinoid necrosis of the vessel walls was unremarkable, but endothelial swelling and scant red blood cell (RBC) extravasation were noted. Fibrosis and sclerosis of collagen fibers were noted on the deep dermis. Results of laboratory examinations, including complete blood count (CBC), routine chemistry, c-reactive protein (CRP), syphilis and human immunodeficiency virus (HIV) tests, and serum immunoglobulin electrophoresis, were all negative or within normal limit. A diagnosis of erythema elevatum diutinum was made based on the clinical and histological findings. The patient was treated with prednisolone, dapsone, colchicine, and intralesional injection of triamcinolone and showed slight improvement after treatment for 8 months. (Korean J Dermatol 2019;57(7):387~ 390).