Erythema Ab Igne: Decoding Skin Presentations of Vasculitis Mimickers in Autoimmunity

A female patient in her 50s with systemic lupus erythematosus presented with a widespread eruption on her back, first noticed by her daughter 3 months ago. On initial rheumatologic evaluation, concern was raised for vasculitis or a thrombotic vasculopathy given the reticulated skin discoloration in the setting of systemic lupus erythematosus. She was referred to the Department of Dermatology for evaluation, where physical examination revealed a well-appearing patient with Fitzpatrick Skin Type IV. Examination of the back demonstrated an asymptomatic, reticulated, hyperpigmented eruption, extending from the mid-upper to lower back, including the flanks (Figure 1). No evidence of purpura was noted.