Unilateral Thyroid-Associated Orbitopathy as the Only Sign of Occult Celiac Disease: Effective Treatment with a Gluten-Free Diet.

A 36-year-old Caucasian woman presented to our clinic with unilateral orbitopathy. In the previous 3 months, she had noticed that her right eye was “more opened” with irritation, burning, increased tearing, and episodic retrobulbar pain. Her past medical history included only a diagnosis of euthyroid Hashimoto thyroiditis (HT) 13 years before. Examining her previous clinical reports, we detected positivity for anti-transglutaminase antibodies (anti-tTg Ab), which dated back to the time of the diagnosis of HT and had not been further investigated. Since then, she reported a varied diet, regular menstruation, and normal bowel movements. She reported no history of pregnancy, abortions, smoking habit, or allergies. Her only medication was a history of contraceptive pill use for several years. Thyroid ultrasonography showed the typical features of chronic autoimmune thyroiditis, while blood tests confirmed a normal thyroid-stimulating hormone (TSH) level (3.5 mU/L), along with strong positivity for anti-thyroglobulin and anti-thyroperoxidase antibodies (anti-Tg Ab and anti-TPO Ab). A whole-eye examination demonstrated, in the right eye, mild eyelid swelling, mild redness of the conjunctiva, and upper eyelid retraction (eyelid aperture 12 mm vs. 9 mm in the left eye). No sign of orbitopathy was found in the left eye. There was no proptosis (both eyes 18 mm), and visual acuity was normal in the absence of diplopia. On a physical examination, anthropometric parameters were normal (weight 55 kg, height 162 cm, body mass index 21 kg/m), and the patient’s vital signs were also in the normal range. The thyroid was palpable with an increased texture, in the absence of signs of hyperfunction or hypofunction. As expected, anti-TSH receptor antibodies (TRAb) were positive (2.8 times above the upper limit). Orbital magnetic resonance imaging showed mild dacryoadenitis and thickening of the levator palpebrae muscle, restricted to the right orbit. We assessed the patient’s orbitopathy as active according to the Clinical Activity Score (3 points) and mild according to the European Group of Graves’ Orbitopathy classification. Because of the finding of anti-tTg Ab positivity, which had been neglected 13 years before, and the described association between thyroid autoimmunity and celiac disease (CD), we decided to further investigate this possibility, and again obtained an increased concentration of these autoantibodies. Duodenal endoscopy was thus performed, revealing increased intraepithelial lymphocytes, hyperplastic crypts, and severe villous atrophy (Marsh 3c CD). We then confirmed the diagnosis of unilateral and euthyroid thyroid-associated orbitopathy (TAO) in a patient with CD. Therefore, the patient was advised to start a gluten-free diet (GFD) and she agreed. The patient then noticed a progressive improvement of ocular signs and symptoms. Three months later, a blood test revealed that serum TRAb and anti-tTgAb had