NAIL AND SKIN HYPERPIGMENTATION ASSOCIATED WITH HYDROXYUREA THERAPY FOR POLYCYTHEMIA VERA

A 63‐year‐old black woman presented with a complaint of nail and skin darkening for 5 months. Past medical history included polycythemia vera, hypertension, angina, and hi‐atal hernia. For several years the patient's medications had included isosorbide dinitrate, iron sulfate, propranolol, and sucralfate. The only recent new medication was hydrox‐yurea (500 mg to 1.5 g daily), which the patient had started for polycythemia vera 8 months prior to presentation. She now complained of asymptomatic hyperpigmentation of the finger and toenails, which had begun proximally and extended distally over time. She also noted increased pig‐mentation of her face, neck, arms, and buccal mucosa. Physical examination revealed pigmentary changes in all the nails. Dyschromia varied from blue‐grey to brown‐black. Three different patterns of pigmentation were noted: trans‐verse and longitudinal bands that alternated with areas of lighter discoloration (Fig. 1) and diffuse hyperpigmentation (Fig. 2). The nail plates and the proximal and lateral nail folds had a normal morphology aside from the color changes. Macular brown pigmentation was present on the patient's face, neck, lower arms, palms, and buccal mucosa (Fig. 3). The patient noted that the pigmentation in all of these areas began after the hydroxyurea was started; those areas of skin and mucosa had previously been normal. Lab‐oratory results were significant for a mild anemia, hemoglo‐bin 11.4 g/dL, and hematocrit 35.2%. The patient refused nail or skin biopsy. The patient also noted increased “hardness” of the nails, which made it difficult for her to cut them. Microscopic observation of sections prepared from nail clippings revealed a keratinjzed layer with scattered finely granular brownish pigment. Fontana Masson and Schroml's stains for melanin were positive, and Pearl's stain for iron was negative.