Thyroid autoimmunity associated with recurrent aphthous stomatitis

Recurrent aphthous stomatitis (RAS) is an autoimmune disorder characterized by the periodic appearance of aphthous lesions on the oral mucosa. TH1 cytokines plays a key role in the aetiopathogenesis. Autoimmune thyroid disease (ATD) is the most common autoimmune disease and is frequently accompanied by various other autoimmune diseases.

To investigate the frequency of ATD which has not been studied in the patients with RAS.

Ninety patients and 30 healthy volunteers were included into the study. The serum samples were assayed for thyroid stimulant hormone (TSH), free and total triiodothyronine (fT3, TT3), free and total thyroxine (fT4, TT4), thyroglobuline, anti-thyroid peroxidase antibody (anti-TPO) and anti-thyroglobuline antibody (anti-TG) levels. Thyroid ultrasonography was performed as well.

In RAS patients, the fT3, TT3 levels were higher; whereas the fT4 levels were lower that the control group (P < 0.05). The anti-thyroid antibody was positive in 31.11% of the patients with RAS, and in only 10% of the individuals in the control group (P < 0.05). The mean anti-TG level was also higher in the RAS group. Ultrasonography revealed nodules in 28.8% of the patients with RAS and in 16.7% of the individuals in the control group (P < 0.05). The sT4 levels were lower and the TSH, anti-TPO and anti-TG levels were significantly higher in the RAS patients with thyroid nodules than the RAS patients without nodules (P < 0.05).

These results may be related to either the advance age of the patients or the increased duration of the autoimmune activation which may affect the thyroid.

The frequency of thyroid autoimmune-related problems was higher in patients with RAS. It would be worthy of searching autoimmune thyroid disorders in patients with RAS.