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.
Updated August 01, 2016. Dry, itchy skin can be unbearable. Dry skin can happen any time during the year, but is most prevalent in winter (hence the term, winter itch). Find out why your skin tends to be dry in winter and how to solve dry hands, feet, body, face and lips year-round.