Sweet syndrome and thyroid diseases: a case-based review of a possible association.

Sweet syndrome, also known as acute febrile neutrophilic dermatosis, is a rare dermatological condition characterized by the abrupt onset of tender, erythematous skin lesions, often presenting with fever and systemic inflammation. It is commonly associated with infection, malignancy, and medication exposure. Isolated case reports have described the co-occurrence of Sweet syndrome and thyroid disease, but these reports have not previously been collected or appraised together. A case-based narrative review was conducted using published case reports and case series describing patients with both conditions. Eight cases were identified, involving Hashimoto thyroiditis, subacute thyroiditis, transient autoimmune thyroiditis, Graves' disease, and papillary follicular thyroid carcinoma. These reports suggest a possible association rather than a causal relationship; neither the direction nor the mechanism of any such relationship can be determined from the available evidence, and confounding, diagnostic lag, and chance co-occurrence remain plausible explanations. The temporal relationship between the two varies, with Sweet syndrome occurring before, concurrently with, or after the thyroid disease diagnosis. Most cases of Sweet syndrome improved with corticosteroids, and outcomes for both diseases were generally favorable with appropriate management. Given that the existing literature is limited to case reports, the true prevalence of this co-occurrence remains unknown. Larger comparative studies are needed to determine whether a meaningful association exists.