Abstract
Angioedema without urticaria (AEwU) is an uncommon manifestation of autoimmune thyroid disease (AITD), rarely reported in the pediatric population. A 12-year-old boy presented with recurrent episodes of angioedema affecting the lips and eyelids for 6 months, unresponsive to antihistamines. There were no systemic symptoms, wheals, or identifiable allergic triggers. Laboratory evaluation revealed normal C1-inhibitor levels and function, ruling out hereditary angioedema. Notable findings included eosinophilia (14.4%) and elevated serum Immunoglobulin E levels (1617 IU/mL), while bone marrow flow cytometry and serum tryptase levels were normal. Autoimmune screening identified AITD with overt hypothyroidism (thyroid-stimulating hormone: 34 μIU/mL). A diagnosis of AEwU secondary to AITD was considered. Initiation of levothyroxine (62.5 μg/day) led to symptom resolution within 3-4 days, with no recurrence in eight months. AEwU secondary to AITD is a diagnosis of exclusion and should be considered in patients with unexplained angioedema after ruling out hereditary and allergic causes.