Sweet Syndrome: Clinical Presentation, Malignancy Association, Autoinflammatory Disorders and Treatment Response in a Cohort of 93 Patients with Long-term Follow-up

Abstract

Sweet syndrome is a neutrophilic dermatosis associated with multiple disorders. This retrospective case-series study of patients with Sweet syndrome in a tertiary hospital in Spain from 2001 to 2021, explores clinicopathological characteristics of Sweet syndrome and variables associated with malignancy, presence of autoinflammatory disorders and differences between histological subtypes. A total of 93 patients were identified: 30% idiopathic, 34% malignancy-associated, 29% reactive to infections or drug-associated, and 6% with an autoimmune/inflammatory condition. Acute myeloid leukaemia was the most common malignancy (16/93) followed by myelodysplastic syndrome (7/93). Patients with acute myeloid leukaemia presented isolated flares, marked cytopaenia and rapid response to treatment, whereas myelodysplastic syndrome followed a chronic-recurrent course. The most frequent associated medications and inflammatory disorders were filgrastim and hydroxyurea (n = 2); and inflammatory bowel disease (n = 4). In addition, 3 patients were diagnosed with VEXAS syndrome. Male sex (p = 0.006), fever (p = 0.034), increased erythrocyte sedimentation rate (p < 0.001), anaemia (p < 0.001), and thrombocytopaenia (p < 0.001) were associated with malignancy. Histologically, patients were classified as classic (60%), histiocytoid (22.5%) or subcutaneous (15%), with pain (p = 0.011) and nodules (p < 0.001) being associated with subcutaneous-Sweet syndrome. Sweet syndrome in the context of cytopaenia should alert the presence of malignancy. An acquired autoinflammatory condition should be explored in relapsing Sweet syndrome with myelodysplastic syndrome. A minimum follow-up of 6 months is recommended.

Fig. 1

Clinical presentation of Sweet syndrome (SS). The main types of lesions found in this study are shown here. Of note is the finding that different morphologies can coexist in the same patient (g). (a, b) Erythematous, oedematous, and infiltrated plaques on the trunk. (c, f) Grouped and pleomorphic pustules, with an erythematous base, affecting (c) the hands and (f) the face. (d) Indurated, oedematous, non-grouped, erythematous papules, asymmetrically distributed, in the upper anterior trunk. (e, h) Isolated, seropurulent bullous lesions on the elbow. (g) Pleomorphic lesions consisting of atypical targetoid plaques, with eroded bullous central lesions and peripheral pustular lesions on the leg. (i) Indurated, ill-defined, erythematous nodules asymmetrically distributed on the legs. (b) and (d) are from 2 patients with VEXAS syndrome.