Sweet’s Syndrome UK Day is observed in the United Kingdom every June 2 to promote awareness of Sweet’s syndrome, also known as acute febrile neutrophilic dermatosis, a rare autoinflammatory disease characterized by sudden fever and painful skin lesions. The syndrome was first described by English dermatologist Robert Douglas Sweet in 1964 and is associated with a dense infiltration of neutrophils in affected tissues. Symptoms include fever, reddish-brown skin lesions, fatigue, and joint pain, with diagnosis typically involving clinical examination, blood tests, and skin biopsies. There are three major forms of Sweet’s syndrome: classic (idiopathic), malignancy-associated, and drug-induced. The day is organized by Sweet’s Syndrome UK, a patient group dedicated to supporting individuals diagnosed with the condition, and aims to improve diagnosis rates among medical professionals and the public.