Q.I have a severe keloid problem, and in areas of my body where there has been no trauma or cuts. The two keloids that cause me the most grief are located from ear to ear under my neck and on my chest. Both are large and painful all the time. I have been to five different doctors but have not found any relief. Can you please help?

- Las Vegas, Nev.

A. A keloid is an overgrown scar left in the wake of skin injuries such as surgical incisions, lacerations or burns. They need not be major injuries. Keloids can result from inflammation caused by ear piercings, tattoos, pimples, ingrown hairs or even minor mechanical trauma such as the rubbing of skin or bumping into an object. The initial "injury" may have been so slight that you forgot about it or never even noticed it.

By contrast, the resulting keloids are hard to miss. While the normal injury-repair process is limited to what is needed to heal the wound - that is, the body "knows" when to stop creating new tissue - a keloid results from an abnormal response that just keeps on going. As a result, the scar may be raised, thick and extensive. It can itch, sting or burn. If large enough, the scar may even interfere with movement.

Some individuals are predisposed to forming keloids. For unknown reasons, people with darker skin - those of African or Asian descent, for instance - tend to be more susceptible. And recurrence is common.

A widely used treatment is injection of a corticosteroid directly into the abnormal tissue. Typically, three or four such treatments spaced about a month apart will trade a raised keloid for a flat scar. As such, this treatment is successful in some 80 to 90 percent of patients with smaller keloids.

Larger and more extensive keloid formations typically require surgical removal - by scalpel, electric knife (electrosection) or laser, depending on the surgeon's expertise and the nature of the keloid. A carbon dioxide laser is the gold standard among such tools. Its advantages include a better delineation of target tissue from surrounding tissue, less bleeding and a lower rate of keloid recurrence after removal.

Because surgery itself causes an injury - and can therefore result in another keloid - it is generally complemented by other methods. Most dermatologists recommend corticosteroid injections or other treatments, such as silicone dressings or compression therapy to mechanically flatten the scar formation. At the other end of the spectrum, topical imiquimod or "advanced injectables" such as bleomycin, interferon, or 5-fluorouracil - drugs that work at the cellular level to disable the process of keloid-tissue formation - have shown promise and are coming into use, especially for the more intractable cases.