A child with fever presents with multiple tender erythematous skin lesions. On microscopic examination the skin lesions are seen to have neutrophilic infiltration in the dermis. What is the diagnosis?

Sweet's syndrome, (acute febrile neutrophilic dermatosis) although vasculitis type changes may be seen histologically. It is not a vascular disease. Intense neutrophilic inflammation of the skin is one of its most striking characteristic. Sweet's syndrome is also associated with inflammatory bowel disease and infections like chlamydia, streptococcus. Ref: Acute adult dermatology: Diagnosis and management, by Daniel Creamer, Jonathon Barker, Page 94.