Acute diffuse facial edema as the first clinically recognized manifestation of Hashimoto's thyroiditis: A case report.

We report a case of acute diffuse facial edema as the first clinically recognized manifestation of Hashimoto's thyroiditis in a young woman. The patient presented with sudden-onset nonpitting facial swelling, although she had experienced mild systemic symptoms, including constipation and cold intolerance, for several months. Laboratory evaluation revealed markedly elevated thyroid-stimulating hormone levels, reduced free thyroxine concentrations, and positive thyroid autoantibodies, confirming primary hypothyroidism secondary to Hashimoto's thyroiditis. Levothyroxine therapy resulted in rapid improvement of the facial edema and restoration of euthyroid status during follow-up. This case highlights that hypothyroidism may present with atypical cutaneous manifestations and suggests that thyroid function testing should be considered in patients presenting with unexplained localized swelling.