A 48‐year‐old Caucasian man recounted the onset of keratotic papules on the trunk at the age of 8 years, with subsequent spread to the forearms, scalp, and forehead. His most severe disease was present on the legs. He complained of pain, itching, and noted exacerbations in the summer and with sweating. The family history was negative.On physical examination, the most striking finding was that of extensive, markedly hyperkeratotic plaques on the lower legs >(Fig. 1). His scalp, forehead, chest, and back exhibited mild involvement, with scattered brown keratotic papules, while his forearms showed mildly hyperkeratotic plaques. Flat‐topped brown papules were present on the dorsum of the hands, with a few keratotic papules on the palms, and a few nails with distal notching and red longitudinal streaks. There were no palmar pits or oral mucosal lesions.Extensive hyperkeratotic plaques on the legsimageA shave biopsy was performed of a plaque on the leg, and showed a papillomatous and markedly hyperkeratotic lesion >(Fig. 2). Suprabasal acantholysis in the elongated rete produced characteristic lacunae. The acantholysis was associated with dyskeratosis including corps ronds and grains >(Fig. 3). Together, these features were characteristic of Darier's disease.Suprabasal acantholysis with characteristic lacunae. Original magnification, × 52imageTypical corps ronds and grains. Original magnification, × 488imageTreatment years earlier with topical retinoids, topical steroids, topical keratolytics, and multiple oral antimicrobials had been unsuccessful, and isotretinoin had been discontinued due to elevated triglycerides. Treatment was initiated with acitretin and, after 3 months, mild improvement was noted