Sweet's syndrome: a clinical entity need to discriminate against acute haematogenous periprosthetic joint infection.

Sweet's syndrome (SS) or acute febrile neutrophilic dermatosis is an uncommon condition. It is characterized by fever, polymorphonuclear leukocytosis, painful erythematous cutaneous plaques, and dense dermal infiltrate of neutrophils without vasculitis at the site of skin lesions. Lesions in SS might enlarge and coalesce with increasing dermal oedema, resulting in pseudo-vesicular appearance mimicking joint infections. Here, a rare case of SS mimicking acute haematogenous periprosthetic infection in a 74-year-old woman with a history of total knee arthroplasty is reported. This report aims to elaborate clinical various manifestations of SS in a patient with a history of total knee arthroplasty. In addition, this report describes how to discriminate inflammation between SS and periprosthetic joint infection. Level of evidence V.