1 An adenoma is a part of the gland that has walled itself off from the rest of the gland, forming noncancerous (benign) lumps that may cause an enlargement of the thyroid. Not all adenomas produce excess T-4, and doctors aren't sure what causes some to begin producing too much hormone.  Thyroiditis.
Scratching Itchy Skin Causes Brain To Release Hormone Serotonin, Intensifies Itchy Sensation. While a good scratch may temporarily relieve you of your itch, it actually stimulates serotonin in the brain that intensifies the itchy feeling.
Why Do I Itch When I Get Hives? Question: Why do I itch when I get hives? Answer: In the case of hives from any cause we believe that there are skin cells involved in the process. These skin cells are also called mast cells and they contain a high level of the itch chemical histamine.