Thrombocytopenia probably induced by acitretin.

Retinoids are nonsteroidal hormonal compounds related to retinol. They were discovered more than 50 years ago and have various biologic effects. The oral retinoids currently used in dermatology have different indications and include isotretinoin, acitretin, bexarotene, and alitretinoin. We present the case of a patient who developed thrombocytopenia that was probably induced by acitretin. The patient was a 78-year-old man with hypertriglyceridemia that had been controlled with fenofibrate for the previous 5 months. He consulted with lesions on the hands that had appeared with a burning sensation 8 months previously. Physical examination revealed delimited hyperkeratotic plaques on the palms and dorsum with nail pitting. He was diagnosed with psoriasis. The results of a complete blood count and biochemistry were normal, and treatment was started with acitretin (Acitretina IFC, 25 mg/d). The follow-up analysis performed 6 weeks later revealed a platelet count of 6000/ L (previous, 177 000/ L). The remaining results were normal (hemoglobin, 15.8 g/dL; leukocytes, 7900/ L). The patient was asymptomatic, with no bleeding, fever, or other manifestations. A complete blood workup (clotting, biochemistry [kidney profile, liver profile with lactate dehydrogenase], antinuclear antibodies, anti-DNA antibodies, lupus anticoagulant, anticardiolipin antibodies, complement, electrophoresis, immunoglobulins, thyroid hormones, vitamin B12, folic acid, and serology [hepatitis B and C, human immunodeficiency virus]) was performed to rule out possible causes of thrombocytopenia. The results were normal. Abdominal ultrasound revealed fatty liver disease with no splenomegaly. Specialists from the hematology department decided to suspend acitretin as a potential cause, since it had been started only a short time previously. Fenofibrate was maintained, and intravenous immunoglobulin was started (0.4 g/kg in 3 doses), as was methylprednisolone (1 mg/kg/d, tapering dose). The platelet count returned to normal 4 weeks later (226.000/ L). The skin lesions were treated with topical corticosteroids. The complete blood count remained unaltered 6 months later. Acitretin is a second-generation monoaromatic retinoid. It is an active metabolite of its precursor, etretinate, and has been marketed since 1997. Acitretin is indicated for severe psoriasis, pustular psoriasis, congenital ichthyosis and ichthyosiform disorders, cutaneous and mucous lichen planus, and severe disorders with dyskeratosis and/or hyperkeratosis. It has an antiproliferative effect on psoriatic plaques, reducing thickness, erythema, and desquamation. It also has an anti-inflammatory effect. Given that its pharmacokinetics, effectiveness, and adverse