Hot answers to some 'bad hair' problems.

One day you notice a patch of coarse, unmanageable hair. When that bad hair day extends into the next month and the affected area only grows, panic takes hold. You haven't changed your diet, gotten sick, or altered your hair styling habits. So what's going on? The answer may prove as simple as a hairy hair dryer, dermatologists reported this week.

Since 1986, the medical literature has described three women with localized patches of "bubble hair"- strands rendered coarse, kinky, and brittle by the development of internal bubbles. Since the women had been healthy, the reports suggested the bubbles probably resulted from trauma to hair possessing some genetic defect, notes Susan P. Detwiler of the University of North Carolina (UNC) School of Medicine in Chapel Hill.

Last year, Detwiler encountered another case of bubble hair (upper photo). While the patient did not use hot rollers or curling irons, swim frequently in chlorinated pools, or have a permanent wave, she did blow-dry her shoulder-length tresses twice daily.

Watching that patient use her dryer, Detwiler says she "noticed that [the woman] preferentially positioned it near the affected area." Subsequent examination revealed that clogs of matted hair caused the dryer to overhear. Removing the clogs reduced the dryer's output temperature from more than 300 degrees C to roughly 140 degrees C

Detwiler then exposed hair from 16 adults, a cat, and a dog to heat from a range of sources. At the American Academy of Dermatology meeting in Washington, D. C, this week, Detwiler and Robert A. Briggaman, also of UNC reported finding that everyone's hair will form gas bubbles (lower photo) - "an intermediate stage of hair combustion "if exposed to heat in excess of 175 degrees C to 215 degrees C. A report of the work will appear in the January JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY.