What Causes Hair Loss?

Here are some of the things that can cause hair loss in teens:

• Illnesses or medical conditions. Endocrine (hormonal) conditions, such as uncontrolled diabetes or thyroid disease, can interfere with hair production and cause hair loss. People with lupus can also lose hair. The hormone imbalance that occurs in polycystic ovary syndrome can cause hair loss in teen girls as well as adult women.
• Medications. Some medications that have hair loss as a side effect may be prescribed for teens. These include acne medicines like isotretinoin, and lithium, which is used to treat bipolar disorder. Diet pills that contain amphetamines also can cause hair loss. Chemotherapy drugs for cancer are probably the most well-known medications that cause hair loss
• Alopecia areata. This skin disease causes hair loss on the scalp and sometimes elsewhere on the body. It affects 1.7% of the population, including more than 5 million people in the United States. Alopecia areata (pronounced: al-uh-pee-shuh air-ee-ah-tuh) is thought to be an autoimmune disease, in which the hair follicles are damaged by a person's own immune system. (In autoimmune diseases, the immune system mistakenly attacks healthy cells, tissues, and organs in a person's body.) Alopecia areata usually starts as one or more small, round bald patches on the scalp. These can get bigger, and in a small number of cases, can progress to total hair loss. Both guys and girls can get it, and it often begins in childhood. The hair usually grows back within a year, but not always. Sometimes people with alopecia areata lose their hair again.
• Trichotillomania (pronounced: trik-o-til-uh-may-nee-uh). Trichotillomania is a psychological disorder in which people repeatedly pull their hair out, often leaving bald patches. It results in areas of baldness and damaged hairs of different lengths. People with trichotillomania usually need professional help from a therapist or other mental health professional before they are able to stop pulling their hair out.
• Hair treatments and styling. Having your hair chemically treated, such as getting your hair colored, bleached, straightened, or permed, can cause damage that may make the hair break off or fall out temporarily. Another type of baldness that results from hair styling actually can be permanent: Wearing hair pulled so tightly that it places tension on the scalp can result in a condition called traction alopecia. Traction alopecia can be permanent if the style is worn for a long enough time that it damages the hair follicles.
• Poor nutrition. Poor eating can contribute to hair loss. This is why some people with eating disorders like anorexia and bulimia lose their hair: The body isn't getting enough protein, vitamins, and minerals to sustain hair growth. Some teens who are vegetarians also lose their hair if they don't get enough protein from non-meat sources. And some athletes are at higher risk for hair loss because they may be more likely to develop iron-deficiency anemia.
• Disruption of the hair growth cycle. Some major events can alter the hair's growth cycle temporarily. For example, delivering a baby, having surgery, or going through a traumatic event can temporarily cause shedding of large amounts of hair. Because the hair we see on our heads has actually taken months to grow, a person might not notice any disruption of the hair growth cycle until months after the event that caused it. This type of hair loss corrects itself.
• Androgenetic alopecia. Among adults, the most common cause of hair loss is androgenetic (pronounced: an-druh-juh-neh-tik) alopecia, sometimes called male-pattern baldness. This condition is caused by a combination of factors, including hormones called androgens and genetics. Sometimes, the hair loss can start as early as the mid-teen years. It also can occur in people who take steroids like testosterone to build their bodies.