Sleep hyperhidrosis is extreme sweating during sleep. Sometimes night sweats are related to primary hyperhidrosis (people that are prone to extreme hyperhidrosis night or day). However, they can be a distinct problem due to a medical condition. There are several possible causes, including menopause for women, febrile illness, sleep disorders like sleep apnea. In very rare cases, doctors may even consider more severe disorders such as tumors, hyperthyroidism or other medical disorders.

The underlying causes of the hyperhidrosis are taken into consideration when making a treatment decision.