Primary hyperhidrosis must be distinguished from secondary hyperhidrosis, which can start at any point in life. For some, it can seem to come on unexpectedly. The latter form may be due to a disorder of the thyroid or pituitary gland, diabetes mellitus, tumors, gout, menopause, certain drugs, or mercury poisoning. Such secondary forms may have more serious consequences than just hyperhidrosis, making medical consultation advisable.

There are four types of sweats:

1. Diaphoresis: Diaphoresis is a cold sweat. Diaphoresis is excessive sweating commonly associated with shock and other medical emergency conditions. It is distinguished from hyperhidrosis by the “clammy” or “cold state” state of the patient.
2. Primary Hyperhidrosis: Primary hyperhidrosis is a condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature. This is not a cold sweat.
3. Secondary Hyperhidrosis: Secondary hyperhidrosis is a condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature that is secondary to an underlying pathologic process such as infections, disorders of the thyroid or pituitary gland, diabetes mellitus, tumors, gout, menopause, certain drugs, or mercury poisoning. This is not a cold sweat.
4. Night sweats: Sleep hyperhidrosis, more commonly known as the night sweats, is the occurrence of excessive sweating (hyperhidrosis) during sleep. The sufferer may or may not also suffer from excessive perspiration while awake.

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