Development of acquired haemophilia A in a patient treated with alemtuzumab for multiple sclerosis.

This case illustrates a 36-year-old man who presented with a factor VIII (FVIII) inhibitor (acquired haemophilia A) with cutaneous bleeding and a significant thigh haematoma. No traditional risk factors for the development of a FVIII inhibitor were identified. However, previous treatment with alemtuzumab for multiple sclerosis was noted in the patient's history.