Vascular Inflammation (Vasculitis) in Sweet Syndrome: A Clinicopathologic Study of 28 Biopsy Specimens From 21 Patients

Background Sweet syndrome is characterized by painful, erythematous plaques of rapid onset accompanied by fever. Absence of vasculitis is a histologic criterion for diagnosis. However, recent reports suggest that vasculitis should not exclude the diagnosis. We hypothesized that vasculitis can occur in Sweet syndrome and that it represents an epiphenomenon rather than a primary immune-mediated process. Design Skin biopsy specimens from patients with Sweet syndrome were reviewed to determine the prevalence of vasculitis. The clinicopathologic features of cases with vasculitis were evaluated for statistically significant associations. Specimens with vasculitis underwent immunofluorescence staining. Setting University department of dermatology, university hospital, and private practice. Patients Medical records and biopsy specimens of 21 patients meeting diagnostic criteria for Sweet syndrome were reviewed. Interventions None. Results The prevalence of vasculitis was 29% (6 of 21 patients). There was a significant association of vasculitis with lesions of longer duration ( P = .02). Vascular immunoglobulin and complement could not be demonstrated in cases of Sweet syndrome with vasculitis. Conclusions Vasculitis is not a primary, immune-mediated process in Sweet syndrome but occurs secondary to noxious products released from neutrophils. Blood vessels in lesions of longer duration are more likely to develop vasculitis than those of shorter duration because of prolonged exposure to noxious metabolites. Vasculitis does not exclude a diagnosis of Sweet syndrome.