Sweaty hands are a symptom of diseases such as focal hyperhidrosis, panic disorder and stress, according to WebMD and Mayo Clinic. Focal hyperidrosis produces sweaty palms for no apparent reason and the sweating stops when the patient is asleep, says Mayo Clinic.
People with focal hyperhidrosis, also called primary hyperhidrosis, generally sweat from eccrine sweat glands. Hands have numerous eccrine sweat glands, according to WebMD. When a person is overheated, moving around, feeling emotional or experiencing hormonal activity, nerves in the body activate the sweat glands. When the nerves overreact, it causes hyperhidrosis.
Patients rarely experience hand sweating or palmar hyperhidrosis at night, because sympathetic activity in the body decreases to a minimal level. Blood pressure and pulse rate also decline, according to the Center for Hyperhidrosis.
Excessive sweating is harmless most of the time, and in some cases doctors do not know why a patient sweats too much. In other cases, hyperhidrosis may be a symptom of another medical condition, according to WebMD. For example, a panic attack, an anxiety disorder that strikes without warning, produces cold or sweaty hands.
Other illnesses such as obesity, hyperthyroidism, psychiatric disorders and menopause can cause excessive sweating, says the Center for Hyperhidrosis.