Q: Why does my husband sweat heavily while sleeping at night? It happens in an air-conditioned room and even in a non-air-conditioned room, but when the weather is cold. His clothes get wet because of the sweat. The sweat is a little smelly. This has happened three times in two weeks.

A:Excessive sweating or hyperhidrosis is defined as sweating beyond the physiological need of the body. Sweating is a way the body regulates its temperature. Sweat is produced by sweat glands located in the skin in various parts of the body. These sweat glands have their highest concentrations in the palms of the hands. The activity of sweat glands is under the control of the sympathetic nervous system and is involuntary. Over activity of the sympathetic nervous system can cause excessive sweating. Excessive sweating or hyperhidrosis is divided into two main categories: Primary hyperhidrosis Excessive sweating in primary hyperhidrosis has unknown aetiology and tends to be localised. This can affect hands (palmar hyperhidrosis); face (facial hyperhidrosis); underarms (axillary hyperhidrosis) and feet (pedal hyperhidrosis). Treatment for primary hyperhidrosis is a multidisciplinary challenge that involves medications, antiperspirants, iontophoresis, and sympathectomy. Secondary hyperhidrosis Excessive sweating in secondary hyperhidrosis has an underlying reason and generally affects the entire body. Conditions causing secondary hyperhidrosis are hyperthyroidism; infections; malignancy; autoimmune disorders; obesity; menopause; diabetes; and psychiatric disorders. Treatment for secondary hyperhidrosis involves eliminating the underlying condition.