Urticaria pigmentosa and acute lymphoblastic leukaemia.

Childhood urticaria pigmentosa is generally considered to have a good prognosis with the majority of cases undergoing spontaneous resolution. However, there have been a number of reports of haematological malignancies occurring in association with urticaria pigmentosa. We describe a child with extensive urticaria pigmentosa and a congenital cardiac anomaly who developed acute lymphoblastic leukaemia and suggest a possible common aetiology.