Eczematous dermatosis and thrombocytosis induced by efalizumab: two new side effects.

Efalizumab was authorized to be put on the market in France starting July 21, 2005. Its efficacy and tolerance profile in plaque psoriasis at a dose of 1 mg kg(-1) weekly in a subcutaneous injection have been studied in phase III trials. At the current moment, more than 3,500 patients have been included in clinical trials. Flu-like symptoms (fever, chills, headaches, nausea, vomiting, myalgia) are the most frequent adverse events. On the skin, a localized papular rash or the aggravation of the psoriasis in an edematous or even pustular form are the two most regularly observed complications. At the biological level, hyperlymphocytosis and a temporary increase in alkaline phosphatases without clinical consequences are the most frequent anomalies. We report 2 adverse events under efalizumab that to our knowledge have never been described: a case of an eczematous rash and a case of thrombocytosis.