Variegate porphyria. Clinical and laboratory features.

Variegate porphyria (VP) is a rare disease infrequently diagnosed in the United States. The typical cutaneous signs of VP, including fragility, bullae, scarring, hypertrichosis, and photosensitivity, are indistinguishable from those of porphyria cutanea tarda (PCT). Inadequate laboratory evaluation of porphyrins present in, or improper interpretation of porphyrin test results from, biologic specimens from patients with VP may lead to inappropriate diagnosis and treatment. Clinical and laboratory data for three such cases of VP are presented. A plasma porphyrin fluorescence criterion which appears specific for patients with VP was observed in all three cases.