Pyoderma gangrenosum in a six-month-old boy.

Pyoderma gangrenosum (PG) is an uncommon, chronic ulcerative condition of the skin that was first described in 1930. It can occur in any age group, but only 4% of the patients are infants or children. An underlying systemic disease is present in approximately 50% of the patients with PG. The most common associations include inflammatory bowel disease, arthritis, lymphoproliferative disorders and chronic recurrent multifocal osteomyelitis (CRMO). PG has been reported in association with CRMO in only a few children whose ages were between 18 months and 12 years. We report a six-month-old boy who was diagnosed as CRMO based on his clinical examination and histological findings. This is the youngest case reported in the literature (under 12 months of age) with PG associated with CRMO.