In Rheumatology there are several diseases that frequently develop cutaneous manifestations creating diagnostic difficulties. The Sweet's syndrome appears as archetype of the neutrophilic dermatosis,which is a group of not infectious illnesses, characterized for a dermic neutrophilic and angiocentric infiltrated. The four main features that define this syndrome are: cutaneous eruption, fever, peripheral neutrophilia and dermic neutrophilic infiltrated without vasculitis on skin biopsy. The authors describe a typical clinical case of Sweet's syndrome, pointing out the multiplicity of clinical situations that can simulate this pathology, making difficult its diagnosis and highlighting the need for suspicious in patients with both musculoskeletal and cutaneous involvement.