Haematological disturbances during long-term valproate therapy.

A 14-year-old boy with mental retardation presented with severe thrombocytopenia, macrocytic anaemia and allergic dermatitis. He had been treated with valproate for seizures since the age of 2 years. Clinical examination showed severe purpura, mucous bleeding and extensive dermatitis. Tests to detect serum direct antiplatelet antibodies were positive and bone marrow examination revealed myelodysplastic abnormalities. Valproate was discontinued and both dermatitis and general condition of the child improved with normalization of the full blood count. This report suggests that valproate may produce both peripheral immune thrombocytopenia and severe bone marrow depression several years after the initiation of the therapy.