Carotenoderma: a possible pit-fall in the immunopathologic diagnosis of pemphigus vulgaris

A 30-year-old woman presented with an orange-yellow discoloration of the skin, most noticeable on the palms and soles and nasolabial folds; sclera appeared normal. The patient had observed the abnormal pigmentation of her skin 3 months earlier and noticed that it had become more evident after a sauna she had taken 2 days before our examination. In the last 3 years the patient's diet included about 2 kg of oranges daily (which are notoriously rich in carotene) following her own original idea. Complete laboratory analyses were normal. In particular, thyroid and liver function tests were in the normal range as were serum lipid levels. The serum carotene levels were 410 mg/dL (NV 20-150 mg/dL) and the levels of vitamin A 68 mg/dL (NV 25-60 mg/dL). A punch biopsy, taken from the palm of the right hand, observed under an optic microscope showed an autofluorescence in the superficial horny layer and a pemphigus-like pattern of intercellular autofluorescence. A month after the interruption of the orange-rich diet, the abnormal coloration of the skin disappeared and serum levels of carotene and vitamin A were normal.