Refractory Chronic Spontaneous Urticaria: A Rare Presentation of Graves' Disease.

Chronic spontaneous urticaria (CSU) is marked by repeated episodes of wheals and/or angioedema lasting more than six weeks and occasionally coexists with autoimmune thyroid disease. Autoimmune thyroid disease may contribute to CSU in a subset of patients, and symptoms can be refractory to conventional antihistamine and corticosteroid therapy. A 33-year-old woman with a history of asthma presented with recurrent widespread urticaria and periorbital angioedema, often triggered by food, resulting in repeated acute care visits. Symptoms were minimally responsive to high-dose antihistamines and systemic corticosteroids. She underwent evaluation for mast cell disorders and neuroendocrine tumors, which were excluded through normal serum tryptase, urinary 5-hydroxyindoleacetic acid, and plasma metanephrine levels. Biochemical testing revealed suppressed thyroid-stimulating hormone (TSH) and elevated free thyroid hormones, with positive TSH receptor antibodies, consistent with autoimmune thyroid disease. Medical management with antithyroid therapy, beta-blockers, and antihistamines achieved biochemical control of hyperthyroidism but did not improve urticaria. Thyroid ultrasound demonstrated diffuse hypervascular enlargement. Given persistent severe CSU and refractory hyperthyroidism, the patient underwent total thyroidectomy. Histopathological examination confirmed autoimmune thyroid disease. Following surgery, urticaria and angioedema resolved completely, with no recurrence at follow-up. This case illustrates a severe autoimmune CSU phenotype likely mediated by overlapping IgE- and IgG-driven mechanisms sustained by active thyroid autoimmunity. The complete resolution of urticaria following thyroidectomy suggests a direct causal relationship. Early recognition of thyroid dysfunction in patients with recurrent or refractory CSU can guide targeted management, prevent repeated hospital visits, and, in select cases, may enable definitive thyroid ablation as a curative approach. Multidisciplinary evaluation and individualized treatment planning are essential for patients presenting with severe autoimmune CSU unresponsive to conventional therapy.