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.
Tweet. There are many reasons for itching. Something is irritating your skin. It could be something you came in contact with or some waste product or toxin trying to work its way out of your body. There could be an infection in the skin. Many people itch when they get too stressed out or worn down. In response to such skin stressors your mast cells may release histamine (an irritant chemical), that magnifies the itching response.