• Pernio is caused by exposure to cold for a long period of time without freezing or by very wet conditions.
• Cryoglobulins are proteins, which are normally dissolved in the blood, that become solids or gels when cold. Cryoglobulinemia is the condition associated with cryoglobulins in the blood, whereby cold exposure leads to bluish discoloration of the fingers or toes.
The formation of hives in response to cold exposure of the skin is called cold urticaria.
• Raynaud's phenomenon refers to constriction of the blood vessels of the hands or feet in response to cold exposure. Raynaud's phenomenon causes white, then blue, then red-colored fingertips and toes and is often painful.
Hypothyroidism, also called underactive thyroid disease, is a common disorder. With hypothyroidism, your thyroid gland does not make enough thyroid hormone.
The thyroid gland is located in the front lower part of your neck. Hormones released by the gland travel through your bloodstream and affect nearly every part of your body, from your heart and brain, to your muscles and skin. The thyroid controls how your body's cells use energy from food, a process called metabolism. Among other things, your metabolism affects your body’s temperature, your heartbeat, and how well you burn calories. If you don't have enough thyroid hormone, your body processes slow down. That means your body makes less energy, and your metabolism becomes sluggish.
If your breathing is fast and shallow, your blood does not receive enough oxygen, thus being unable to transfer heat throughout the body. At the same time, shallow breathing is simultaneously a cause and an effect of tension.