The medical term for an inability to sweat is anhidrosis or hypohydrosis. This condition can be very troublesome. If you don't sweat, your body can't cool itself and is prone to overheat, sometimes dangerously so. Some people are affected with this disorder in only one part of the body or in scattered patches, but it can also affect the entire body. If that's the case, you're at risk of overheating during hot weather, vigorous exercise or when performing demanding physical activity, leading to heat cramps, heat exhaustion or, most dangerous, heat stroke.
Anhidrosis can be due to genetic factors, and it can also develop as a result of disorders that damage the body's autonomic nervous system. That system controls involuntary actions such as digestion, heartbeat, blood pressure, and body temperature. Among the medical disorders that can cause this damage are diabetes, alcoholism, Parkinson's disease, amyloidosis, Sjogren's syndrome, and small cell lung cancer. In addition, skin damage (especially bad burns) can reduce the ability to sweat. Some medications can also interfere with sweating, although sweating goes back to normal when you stop taking them.
No specific treatment exists for anhidrosis, but I would recommend trying acupuncture and hypnosis - both therapies can help with autonomic dysfunction. Beyond that, be careful to prevent your body from overheating: wear loose clothing when it's warm, don't overdress in cold weather, stay indoors on hot days, and be aware of your activity level. You - and the unaffected members of your family - should also learn the symptoms of heat-related illness and what to do if you develop them.
Andrew Weil, M.D.