Hi I am just wondering if anyone knows if there could be a link between Asthma and Underactive Thyroid? I am not confident that I am adequately medicated for the Thyroid problem but GP won't acknowledge this i.e. taking 75 mg Lethyroxine and TSH at 4.3 which I know is too high! I am also struggling to get my recently controlled Asthma under control now. I am also wondering if having a Thyroid problem could make us more sensitive to allergens! Are there many people here that have have both conditions. If so I would love to hear from you. Many thanks.