CLINICAL AND THERAPEUTIC IMPLICATIONS OF THE ASSOCIATION BETWEEN CHRONIC URTICARIA AND AUTOIMMUNE THYROIDITIS

Context. Chronic idiopathic urticaria (CIU) is often associated with autoimmune thyroiditis (AT). Objective. The aim of this study was to analyze the clinical particularities of patients with CIU associated with AT and to evaluate the efficacy of dapsone in such patients. Design. We performed an observational study of patients hospitalized in our clinic between January 2010 December 2013 for moderate/severe chronic urticaria (CU). Subjects and Methods. Data regarding medical history, clinical, paraclinical findings, coexistence of AT and response to treatment were compared between patients with CU and AT and those without AT. Patients continued oral H1 antihistamines. Severe flares required systemic corticotherapy. 11 patients with refractory CIU associated with AT received dapsone treatment. Levothyroxine was administered in patients with hypothyroidism. Results. Among the 210 patients admitted for CU, 39 (92% female) were diagnosed with CIU associated with AT. Patients with CIU associated with AT had a slightly longer disease duration, a higher prevalence of angioedema (25.6% vs. 16.7%) and a more frequent need of systemic corticotherapy for urticaria exacerbations (46.2% vs. 30.4%). All 39 patients achieved significant clinical improvement after a mean period of 4 weeks based on urticaria activity score (UAS) 7 (p<0.0001). Conclusions. Assays for thyroid autoantibodies and thyroid function should be part of the workup in patients with CU, enabling the diagnosis of autoimmune urticaria. Without correction of the underlying autoimmune mechanisms, CU may persist regardless of conventional treatment. Dapsone represents a therapeutic option in autoimmune CU.