Sweet Syndrome: Acute Febrile Neutrophilic Dermatosis

Overview / DefinitionSweet Syndrome, also known as acute febrile neutrophilic dermatosis, is an inflammatory skin disorder that presents with abrupt-onset painful erythematous plaques and papules. It is characterized histologically by a dense neutrophilic infiltrate in the dermis and is frequently associated with systemic symptoms such as fever and fatigue. This condition can occur idiopathically or secondary to various underlying diseases, particularly malignancies.EpidemiologySweet Syndrome is a rare condition, with an estimated prevalence of 1-2 cases per 100,000 individuals. It predominantly affects women, with a female-to-male ratio of approximately 3:1. The most common age of onset is in the third to fifth decades of life, although it can occur at any age. It is often associated with hematological malignancies, particularly acute myeloid leukemia (AML), and autoimmune diseases.Pathophysiology / MechanismThe exact pathophysiological mechanism underlying Sweet Syndrome remains unclear. However, it is believed to involve an exaggerated immune response, particularly mediated by neutrophils and cytokines. Triggering factors may include infections, medications, and malignancies, leading to the release of pro-inflammatory cytokines such as IL-1, IL-6, and TNF-alpha. These cytokines contribute to neutrophil recruitment and activation, resulting in the characteristic skin lesions.Clinical PresentationPatients with Sweet Syndrome typically present with:Fever: Often exceeding 38°C (100.4°F).Painful erythematous plaques: These lesions may be associated with vesicles, pustules, or bullae.Location: Commonly affects the upper extremities, face, neck, and trunk.Duration: Lesions can evolve rapidly over days to weeks.Additional systemic symptoms may include malaise, arthralgia, and weight loss. The lesions may resolve spontaneously or require treatment, but recurrences are common.Diagnosis / WorkupThe diagnosis of Sweet Syndrome is primarily clinical, supported by histopatholo