Oral 8, A case of pyoderma gangrenosum in association with autoimmune neutropenia of infancy

A 10‐month‐old girl presented in January 2006 with a 10‐day history of a rapidly enlarging 2‐cm ulcer on the left buttock which had not responded to antibiotic therapy. The ulcer had an indurated red border with mild surrounding erythema. Systemic examination was unremarkable. Skin swabs showed skin flora only and subsequent treatment with Trimovate ® (GlaxoSmithKline, Uxbridge, U.K.) cream, mupirocin ointment and oral azithromycin had no effect. A skin biopsy taken 8 days after presentation showed active polymorph infiltration, granulation tissue formation and a heavy mixed inflammatory cell infiltrate within the ulcer. Tissue culture showed Enterococcus faecalis which was felt to represent colonization in the napkin area. A full blood count showed a neutropenia of 0·36 × 10 9 L –1 (normal 1·5–8·5 × 10 9 ) with a raised monocyte count of 1·36 × 10 9 L –1 (0·2–0·8 × 10 9 ). Renal and liver function tests, autoimmune screen, immunoglobulins, vitamin B 12 , folate and C‐reactive protein were normal. A clinical diagnosis of pyoderma gangrenosum was made and the ulcer was treated with topical clobetasol propionate ointment under occlusion, resulting in dramatic improvement within 3 days followed by complete healing over in 2 weeks. The patient subsequently developed mild recurrent ear and upper respiratory tract infections and repeat full blood counts showed a persistent neutropenia < 0·3 × 10 9 L –1 associated with an intermittent monocytosis and thrombocythaemia. In view of the known association between pyoderma gangrenosum and myelodysplasia a bone marrow aspirate was performed which showed normocellular marrow with no cytogenetic abnormalities. Further blood tests showed an IgG granulocyte‐specific antibody in the serum consistent with a diagnosis of autoimmune neutropenia of infancy. She is currently on prophylactic trimethoprim 2 mg kg –1 daily and nystatin suspension, and remains fit and healthy. Autoimmune neutropenia runs a benign clinical course associated with minor infections, and is normally self‐limiting by 24 months of age. 1 Pyoderma gangrenosum is rare in childhood but frequently involves the perianal and genital area in this age group. 2 Recognized associations include inflammatory bowel disease and haematological malignancy, although an association with autoimmune neutropenia of infancy has to our knowledge not previously been described. References 1 Taniuchi S, Masuda M, Hasui M et al . Differential diagnosis and clinical course of autoimmune neutropenia in infancy; comparison with congenital neutropenia. Acta Paediatr 2002; 91 :1179–82. 2 Graham JA, Hansen KK, Rabinowitz LG, Esterly NB. Pyoderma gangrenosum in infants and children. Pediatr Dermatol 1994; 11 :10–17.