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.
Allergic skin reactions â what your doctor calls allergic contact dermatitis -- happen when your immune system overreacts to chemicals that are normally harmless. These chemicals can be in products that you are exposed to over and over, like cleaners, colognes, hair dyes, and personal care items.our skin is one of the first places where allergy symptoms can show up. They often appear 24 to 48 hours later, but can start as late as a week after exposure. Each person may have different chemical allergy symptoms. Some of the most common are: 1  Red skin. 2  Scaly patches. 3  Blisters that ooze.