Acute thrombotic thrombocytopenic purpura following doxycycline treatment of Chlamydia pneumoniae infection in a patient with dermatomyositis.

A 48-year-old white female who was suffering from dermatomyositis and Chlamydia pneumoniae infection, developed acute rapidly fatal thrombotic thrombocytopenic purpura (TTP) following treatment with steroids and doxycycline. As a relationship between TTP and the inflammatory myopathies is now probably well established, it is very likely that our patient's TTP became manifest in association with dermatomyositis. Nevertheless, C. pneumoniae infection and doxycycline therapy cannot be excluded entirely as cofactors responsible for triggering her thrombotic microangiopathy.