Chronic Urticaria as the Sole Clinical Manifestation of Autoimmune Thyroid Disease: A Case Report

Chronic urticaria (CU) is defined as the spontaneous appearance of wheals, angioedema, or both for more than six weeks. In many cases, the cause remains idiopathic; however, increasing evidence supports a strong association with autoimmune disorders, particularly autoimmune thyroid disease (AITD). While thyroid dysfunction is typically considered in the presence of systemic symptoms such as fatigue, weight changes, or menstrual irregularities, CU may occasionally be the sole clinical manifestation. We present the case of a 32-yearold woman who attended an outpatient clinic with a 3-month history of daily itchy wheals without identifiable triggers. Antihistamines provided minimal relief, and no systemic symptoms were reported. Physical examination revealed typical urticarial wheals with no other abnormalities. Initial blood work was unremarkable. Given the chronicity and lack of response to standard therapy, autoimmune screening was performed. Thyroid-stimulating hormone (TSH) and free T4 were within normal limits; however, anti-thyroid peroxidase (antiTPO) and anti-thyroglobulin antibodies were markedly elevated, confirming the presence of autoimmune thyroiditis. Although the patient was euthyroid, she was started on low-dose levothyroxine in consultation with an endocrinologist. Within four weeks, a significant reduction in urticaria frequency and severity was noted. This case highlights the importance of considering autoimmune thyroid disease in patients with refractory CU, even in the absence of thyroid dysfunction. It also underscores the potential benefit of levothyroxine in managing autoimmune-related urticaria. Primary care and outpatient clinicians should maintain a high index of suspicion for AITD in idiopathic CU, as early diagnosis and intervention can significantly improve patient outcomes and quality of life.

Key Words: Chronic Urticaria, Autoimmune Thyroid Disease