If excessive sweating has no underlying medical cause, it's called primary hyperhidrosis. It happens when excess sweating is not triggered by a rise in temperature or physical activity. Primary hyperhidrosis may be at least partly hereditary.
If the excess sweating is due to an underlying medical condition, it's called secondary hyperhidrosis.
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.