Recurrence of thyrotoxicosis after attack of allergic rhinitis in patients with Graves' disease

Graves' disease is frequently aggravated during antithyroid drug therapy; however, little is known of its aggravating factors. We studied 83 patients with Graves' disease who were euthyroid for at least 6 months under antithyroid maintenance therapy, and we examined the relationship between thyrotoxicosis relapse, attack of allergic rhinitis, and peripheral eosinophil increase. Forty-one patients showed thyrotoxicosis relapse; of these, 22 (54%) showed peripheral eosinophil increase, and 14 (34%) had attacks of allergic rhinitis. In the remaining 42 patients without thyrotoxicosis relapse, only 4 (10%, P < 0.001) showed an increase in peripheral eosinophils, and only 3 (7%, P < 0.01) had allergic rhinitis. Recurrence of thyrotoxicosis was observed with the increase in serum levels of TSH-receptor antibodies and increase in eosinophils 2 months after the attack of allergic rhinitis. Three patients with seasonal allergic rhinitis showed thyrotoxicosis relapse at the same time of year within 2 consecutive years. Our findings indicate that allergic rhinitis can be an aggravating factor of Graves' disease and suggest that the preceding increase in peripheral eosinophils can be a predictive indicator of recurrence of thyrotoxicosis during antithyroid drug therapy.