A case of porphyria cutanea tarda induced by oral contraceptive pill therapy is reported, and its unusual presenting sign of onycholysis of the finger nails is noted. Reference is made to the rarity of nail changes in porphyria and the regression of the onycholysis in the patient following therapy is outlined.
PIP: The porphyrias, a group of metabolic disorders characterized by the excess production of porphyrins, or their precursors, are illustrated in a case report of a young woman who had been taking an oral contraceptive, Norinyl-1, for 18 months, and developed porphyria cutanea tarda. The initial symptom had been discoloration of her fingernails diagnosed as onycholysis. Onycholysis is separation of the distal nail plate from its bed. Numerous vesicles, erosions, and pitted scars were noted on the dorsa of her hands and on her face. Hypertrichosis of her face was present. There was also soreness in these regions on exposure to light. Laboratory tests showed increased urinary and fecal uroporphyrins and coproporphyrins. The porphobilinogen test was negative. Serum iron level was raised. Liver function tests were abnormal and hepatic siderosis was present on histologic study of biopsy material. The oral contraceptive was discontinued. Sodium bicarbonate therapy to alkalinize the urine and thus increase porphyrin excretion was not successful. Venesection was then used and 41 of blood were removed over a 4-month period. All symptoms improved rapidly. The patient has been advised to avoid all estrogen-containing preparations and to use an alternative form of contraception.