If you're finding fewer hairs on your head and more in your sink, you may be justifiably concerned. It's normal to shed between 50 and 100 hairs each day, but if you're losing more you could be suffering from excessive hair loss.

The medical term for hair loss is alopecia, and the most common type is known as pattern baldness. The condition affects nearly two-thirds of men and tends to run in families.

A history of hair loss on either side of your family tree increases your chances of being bald. Heredity also influences the age at which balding begins, as well as the extent and the pattern of hair loss.

Male pattern baldness can begin as early as the teen years. In men, hair loss typically starts at the temples and the crown of the head and eventually leads to partial or complete baldness.

Women aren't immune to hair loss: Female pattern baldness is characterized by hair loss at the front, sides and crown of the head. While women can suffer significant thinning, they rarely experience complete baldness.

Another type of hair loss, known as alopecia areata, is rather rare, affecting just about 2 percent of the population. This condition usually produces baldness in small, round patches on the scalp, but hair loss may occur on other parts of the face and body, including the eyebrows, eyelashes and chest.

The exact cause of alopecia areata is unknown, but it is classified as an autoimmune disease. For unknown reasons, the immune system begins to attack the body it is designed to defend.

Unlike pattern baldness, alopecia areata is often a temporary condition, but it can take several years for lost hair to regrow. Another cause of temporary hair loss is telogen effluvium, a condition that may occur following severe emotional or physical distress.

Also, traction alopecia is caused by wearing hairstyles that pull the hair excessively. Extremely tight coifs can damage and scar the scalp, resulting in permanent hair loss.

While some types of hair loss are easily diagnosed, others have less obvious causes. In some cases, a chronic health condition — such as diabetes, lupus or thyroid disease — can be at the root of the problem.

Poor nutrition is occasionally to blame. Extremely low-calorie diets and some fad diets can lead to deficiencies in protein, vitamins, minerals, and other nutrients necessary for hair growth.

Temporary hair loss may be a side effect of certain medications, including those used to treat gout, depression and high blood pressure. Some women may experience hair loss as a result of taking birth control pills.

Medical treatments, including radiation therapy and chemotherapy, can produce temporary hair loss. Childbirth can cause excessive shedding in some new mothers.

Scalp infections, including ringworm, can cause changes on the skin's surface that lead to hair loss. Once the infections are treated, hair growth is usually restored.

There is no sure-fire cure for baldness. But in some cases, it can be successfully treated. Hair loss that is not related to pattern baldness is best managed by your family physician or a dermatologist.

If you've got simple pattern baldness and you want to try a do-it-yourself program, the over-the-counter drug Minoxidil might be your best bet. The product was originally sold under the brand name Rogaine, but cheaper generic alternatives are now available.

Minoxidil should be rubbed into the scalp twice daily to regrow hair and help prevent further loss. The good news is about 25 percent of men and 20 percent of women experience some new hair growth after using the product. But, the bad news is the product must be used daily for as long as you want to keep your new hair.

Men with male pattern baldness often benefit from a prescription medication known as Propecia. Available in the form of a pill, the drug's greatest claim to fame is halting hair loss in the early stages of baldness.

In over 80 percent of newly balding men, daily use of the medication helps slow premature shedding. Propecia isn't approved for use in women, as it may cause serious birth defects in developing fetuses.

Although hair loss is almost always physically painless, many people with the condition suffer some emotional distress. If you're experiencing excessive hair loss, see your doctor. Together, you can get to the root of the problem and decide on a treatment that's right for you.

Rallie McAllister is a board-certified family physician, speaker and the author of several books, including "Healthy Lunchbox: The Working Mom's Guide to Keeping You and Your Kids Trim." Her website is www.rallieonhealth.com. To find out more about Rallie McAllister, M.D., and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.

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