Ecthyma gangrenosum as a very early herald of acute lymphoblastic leukaemia.

Ecthyma gangrenosum is a manifestation of cutaneous infection by Pseudomonas aeruginosa. The lesion may be associated with immunocompromise, in particular neutropenia. We present a case of ecthyma gangrenosum in a previously healthy child who 3 months later developed acute lymphoblastic leukaemia; we use this to illustrate the lack of information on the growth rate of malignant and premalignant leukaemic cells in children.