Pyoderma gangrenosum and interleukin 8

Conflicts of interest: none declared. Sir, Interleukin (IL)‐8 is a potent chemotactic polypeptide for neutrophils.1 We have previously demonstrated that high levels of IL‐8 are immunohistochemically detectable in dermal fibroblasts from ulcers of patients with pyoderma gangrenosum.2 Furthermore, overexpression of IL‐8 using an adenovirus vector in the skin of severe combined immunodeficiency mice has been shown to result in the development of skin ulcers resembling pyoderma gangrenosum.2 To clarify the level and mode (constitutive or transient) of IL‐8 production in this condition, fibroblasts from a patient with pyoderma gangrenosum were isolated and cultured, and IL‐8 levels were measured in the supernatants. Serum IL‐8 levels were also measured. An 81‐year‐old woman presented with a 4‐year history of diarrhoea. A painful skin ulcer had developed in her right breast 2 months prior to examination and had enlarged rapidly. In addition, loss of appetite and appearance of bloody stools began 1 month prior to examination. Ulcerative colitis was diagnosed in the Department of Internal Medicine at Higashi Kobe Hospital and she was admitted. She had not received any pharmacotherapies prior to admission and was treated using mesalazine alone (2250 mg daily for the first 3 weeks and 1500 mg daily thereafter). The patient was referred to the Department of Dermatology in the same hospital for diagnosis of the skin ulcer. The ulcer measured 12 × 10 cm with an erythematous, raised edge on the right breast (Fig. 1a). The ulcer base was irregular and displayed a granular appearance. After obtaining informed consent, skin biopsies were taken from both the edge of the ulcer and uninvolved skin of the left upper arm for the purposes of diagnosis and cultivation of fibroblasts. Biopsy of the ulcer showed nonspecific changes with a dermal infiltrate comprising neutrophils, and to a lesser extent, histiocytes and mononuclear lymphocytic cells (Fig. 1b). Neutrophils were also identified in blood vessels. Extravasation of erythrocytes was present, but no evidence of vasculitis was apparent. Biopsy of uninvolved skin showed normal skin with no infiltration of neutrophils (data not shown). Clinical and histopathological findings led to a diagnosis of pyoderma gangrenosum and the skin lesion was treated using topical sulfadiazine ointment. Mesalazine therapy led to rapid improvements in both ulcerative colitis and pyoderma gangrenosum and the skin ulcer was almost eradicated leaving scar tissue after 6 weeks of mesalazine therapy.