Summary

Sweet's syndrome (SS) is a neutrophilic dermatosis disorder of unknown aetiology, characterised by acute fever, neutrophilia, painful erythematous papules, nodules and plaques, and an infiltrate consisting predominantly of mature neutrophils in the upper dermis. Classical SS is a rare extra-intestinal manifestation of inflammatory bowel disease (IBD). It is more common in Crohn's disease than in ulcerative colitis (UC). There is a predilection for women, and for patients with colonic disease and active IBD. We report the case of a 39-year-old woman with a flare of moderate severity UC treated with mesalazine who presented with a 5-day history of acute fever, painful papules and plaques on forearms and legs, episcleritis and cervical pain. Skin biopsies showed papillary dermis inflammatory cell infiltration composed mainly of neutrophils, without evidence of leukocytoclastic vasculitis or panniculitis, compatible with SS. The patient had an excellent response to systemic corticosteroids. Symptoms promptly improved and skin lesions resolved after 7 weeks.