Alopecia is the general medical term for hair loss. There are many types of hair loss with different symptoms and causes. Male pattern baldness is the most common type of hair loss, making about half of all men at age 50. It usually begins around the twenties or early thirties, and most men have some degree of hair loss in their late thirties. In addition to affecting men, it can sometimes affect women. During the baldness of the female pattern, the hair usually disappears on top of the head.
Alopecia areata causes patches of baldness over the size of a large coin. They usually appear on the scalp but can occur anywhere on the body. It can occur at any age, but occurs especially in teenagers and young adults. Alopecia areata is caused by a problem with the immune system. It is more common in people with other autoimmune conditions, such as an overactive thyroid, diabetes or Down’s syndrome.
Scalp alopecia, also called cicatricial alopecia, is usually caused by complications of another condition. In this type of alopecia, the hair follicle is completely destroyed. This means that your hair does not grow back.
Anagen effluvium is widespread hair loss that can affect your scalp, face and body.
One of the most common causes of this type of hair loss is the chemotherapy of cancer treatment. In some cases, other cancer treatments can also cause hair loss.
Telogen effluvium is a common type of alopecia where there is much widespreadness of the hair, instead of specific bald patches. Your hair may become thinner, but it is unlikely that you will lose everything and your other body hair will usually not be affected.