Efalizumab-induced thrombocytopenia: report of relapse after re-administration

Although a reversible, sometimes severe, drug-induced thrombocytopenia is a recognized adverse drug reaction (ADR) in patients with psoriasis treated with efalizumab, definite proof for the association of thrombocytopenia with efalizumab is still lacking (currently level II evidence for ADR). We report a patient with psoriasis who had two episodes of reversible thrombocytopenia during efalizumab; the first occurred 5 months after introduction of the medication and the second 4 months after re-introduction of efalizumab for relapsing psoriasis. The development of a second episode of thrombocytopenia on re-exposure to efalizumab provides, for the first time in the literature to our knowledge, definite (level I) ADR evidence for efalizumab-induced thrombocytopenia.