What is alopecia? Alopecia is hair loss that can be caused by heredity, aging, disease, medications or lifestyle. The timing and course of hair loss can provide clues to its cause. For example, hair loss that comes on suddenly may be attributed to illness, diet, or medical treatments, such as chemotherapy or radiation. Gradual hair loss that becomes more prominent over the years is likely to be hereditary and a normal occurrence of aging. This form of hair loss, known as androgenetic alopecia, is the most common cause and a natural symptom of the aging process. Sudden, drastic hair loss that occurs over a short period of time should be evaluated by your health care provider, as it can signal underlying disease. Alopecia areata is an autoimmune disease that causes the hair to fall out in patches. Another cause of hair loss is a condition called cicatricial alopecia, in which the hair follicles that produce hair are destroyed. Hair loss can be experienced by people with certain types of anemia, anorexia, and thyroid disease. It is also a side effect of many medications, including those used to treat depression, heart disease, and high blood pressure. Hair loss also occurs in patients undergoing radiation or chemotherapy treatment. Men and women experience hair loss differently. The male pattern of hair loss typically affects the hairline (receding hairline) or top of the scalp, while women tend to experience hair loss over the front or top of the scalp. In the United States, hereditary hair loss affects 80 million men and women, and more than half of all women will experience it at some point in their lives (Source: AgingSkinNet). A number of treatments are available for hair loss. When hair loss is a sign or symptom of an underlying illness, that condition is typically treated first. Options for the more common hereditary hair loss that occurs with aging include both over-the-counter treatments and therapies available from your doctor that encourage the regrowth of hair. Surgical techniques can be used to transplant the hair or area of skin where hair growth occurs to one where it has ceased. Although alopecia is not life threatening, it can suggest underlying illness, especially if the hair loss is sudden. Seek prompt medical care if you experience sudden, unexpected hair loss (occurring over a few weeks or months).