Coexistence of Autoimmune and Allergic Diseases with Autoimmune Thyroid Diseases

ABSTRACT

Background: Sometimes, the patients with autoimmune thyroiditis show certain symptoms despite having serum thyroid hormone levels within the desired range. In addition, the dose of levothyroxine replacement may vary in the patients with hypothyroidism. These factors directly influence clinical practices and may, to some extent, be associated with other immunological/allergic diseases that accompany autoimmune thyroid diseases (ATDs). Purpose: To document the other autoimmune/allergic disorders in patients during follow-up for ATDs.

Materials and Methods: During the study period, 274 patients diagnosed with, and/or at follow-up for Hashimoto’s thyroiditis (HT), and 53 with Graves’ disease (GD) were included in the study. All the patients were examined and were subjected to further investigations when the presence of other autoimmune/allergic diseases was suspected.

Results: A total of 65 patients with HT (23.8%) and seven patients with GD (13.2%) had at least one additional clinical autoimmune/allergic disorder. Twentyeight (10.2%) patients with HT had gastrointestinal disorders (chronic atrophic gastritis and celiac disease), 19 (6.6%) had allergies (asthma, chronic urticaria, and rhinosinusitis), 12 (4.4%) had rheumatological disorders (rheumatoid arthritis), 10 (3.7%) had skin problems (vitiligo and psoriasis), four (1.5%) had endocrinological disorders (hypoparathyroidism, type–1 diabetes mellitus, and hypophysitis), one (0.4%) had hematological disease (idiopathic thrombocytopenic purpura), and one (0.4%) had renal disorder (crescentic glomerulonephritis). The prevalence patterns were similar in the patients with GD. In addition, 50 (18.2%) patients with HT and one (1.9%) with GD were observed to have vitamin B12 deficient-anemia (p=0.001). Furthermore, 28 (10.2%) patients with HT and one (1.9%) with GD had dimorphic anemia (both vitamin B12 and iron deficiencies).

Discussion: The patients with ATDs are prone to additional autoimmune/allergic diseases, and it can be said that the patients with autoimmune thyroid diseases sometimes have more than just thyroid disease. The most involved organ system in both HT and GD is the gastrointestinal tract. This involvement probably plays a role in the exacerbation of some symptoms by causing anemia resulting from a deficiency of both vitamin B12 and iron, especially in patients with HT.