The following column (Dr. Donahue) appeared in the Monday, July 2, 2012 edition of the Harrisburg (Pennsylvania) Patriot-News:

DEAR DR. DONAHUE:

After shampooing my hair, I looked in the mirror and found a large bald patch near my ear. I screamed. I can comb my hair to hide it. Does this mean I am about to lose all my hair? Is there a treatment for it? - A.A.

With a fair degree of confidence, I can say you have alopecia areata, bald patches that vary in size and number. Close to 4.5 million American adults and children suffer from this condition every year. Like so many other illnesses, its the result of an immune system gone berserk. The immune system attacks hair follicles, the skin pores that are homes for each hair. What turns on the immune system to do this is something that waits to be discovered.

As heartbreaking as alopecia areata is in the short run, there is high hope of complete restoration of hair in time. Around 50% will have hair regrowth within a year even if no treatment is given.

Treatments exist to speed the healing process. One is injection of a high-potency cortisone drug, like triamcinolome, into the bald patch. Another treatment consists of applying an allergen directly to the bald spots. The reaction it produces leads to hair regrowth. The allergen often chosen is DPCP, diphenylcyclopropenone. These are only two of the options open to patients.

Hair follicles retain the capacity to regenerate.

Complicated alopecia areata can affect the entire scalp and body hair. These are not common instances, when you consider the entire population of sufferers of this malady.

If you like more detailed information, contact the National Alopecia Areata Foundation on line at www.naaf.org.

(Write to Dr. Donahue at P.O. Box 536475, Orlando, FL 32853-6475.)

Any comments, fellow alopecians?