This is known as sleep hyperhydrosis, whereby profuse sweating occurs during sleep.
Patients typically present with the complaint of excessive sweating during sleep, with or without excessive sweating during waking hours. Some people may find themselves compelled to arise to change their sleepwear.
Some patients may have this disorder for a life; in other patients, the disorder is only temporary.
This condition can occur at any age, but is most commonly encountered in young adults.

Severity:

Mild: bathing or changing of clothes is not needed; may have to turn the pillow or remove blankets.

Moderate: Sleep disturbed by need to arise and wash face or other affected body areas, but no clothing change.

Severe: A bath or change of clothing required.

Types of excessive sweating:

Primary Hyperhidrosis: This type has no identifiable cause and is usually very severe to the extent of impairing normal everyday activities.

Secondary Hyperhidrosis: this type is usually a manifestation of an underlying cause. The potential causes are many,including simply over dressing or putting on too many covers, obesity, endocrine disturbances like diabetes insipidus (the chronic excretion of large amounts of pale urine, acompanied by extreme thirst) or hyperthyroidism (over-active thyroid gland). We also think of obstructive sleep apnea (OSA) where the sweating is related to the sleep restlessness and movements.

Treatment will depend on the underlying cause.