Hello, I have gone through your query and understand your concern. Yes. Both Hives and Sinus problems are related to your Hashimoto s Thyroid. Hashimoto s Thyroid is a autoimmune thyroid disorder. 1. As you have Hashimoto s ( Autoimmune disorder), you are highly suceptible to infections like sinusitis, Ear infections, Recurrent cold, fungal infections 2. Many people with autoimmune disorders have numerous extreme food, chemical and environmental allergies and sensitivities. Thus you are getting hives every time. There are plenty of symptoms like Muscle Weakness, Extreme Fatigue, Sleep Disturbances, Digestive Problems, Anxiety and Depression etc. As you can see, this is an extensive list of autoimmune disease symptoms and it may be hard to believe that these symptoms are in any way connected. You are probably not experiencing all of these signs or symptoms (at least we hope not), but if you are experiencing many of them, you re not alone. It is believed that the symptoms of any autoimmune disease affect the whole body, and consequently the body needs to be treated as a whole. Thus you have to take continue thyroxine since there is no cure for Hashimoto s Thyroiditis. Please take all the measures to control exposure to allergic substances and protect yourself from infection. If necessary take antibiotics for infection and antihistamines for hives as per your treating doctor advice. Hope this helps. Please write back for further queries. Wishing you good health.