Night sweating causes bedding and pajamas to become damp. This is not the result of a warm room or heavy blankets but a medical condition that is caused by several medical disorders and medications. Understanding the causes of night sweating can help people seek medical treatment when night sweats are persistent and bothersome.

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If you are experiencing serious medical symptoms, seek emergency treatment immediately.


Night sweating is an early sign of some types of cancers, especially lymphoma. According to Patients Against Lymphoma, drenching night sweats are known as a B-symptom of lymphoma. B-symptoms are systemic symptoms that affect the entire body. While the exact cause of night sweats in lymphoma patients is not known, it is theorized the body's immune response against malignant cells can cause night sweats and fever.


According to Baylor College of Medicine, 2/3 of women experience hot flashes 1. These hot flashes can occur at night and are often accompanied by excessive sweating. These night sweats are caused by falling levels of estrogen during perimenopause and early menopause. Avoid stress, caffeine, alcohol, spicy foods and hot beverages to reduce or prevent hot flashes and night sweats during menopause.


Antihypertensives, alcohol, heroin, antidepressants, leuprolide, niacin, tamoxifen and drugs used to reduce fevers can cause night sweats. According to the American Academy of Family Physicians, 11 other drugs are labeled with night sweating as a side effect 2. They are donepezil, saquinavir, cyclosporine, indinavir, zalcitabine, rituximab, pegaspargase, daclizumab and interferon.


Several infections can cause night sweats because of the way the immune system responds to infectious organisms. Infectious mononucleosis, HIV, endocarditis, tuberculosis, coccidioidomycosis, histoplasmosis and Mycobacterium avium complex are known causes of night sweating.

Low Blood Sugar

Hypoglycemia, also known as low blood sugar, can occur at night. This is known as nocturnal hypoglycemia and is a known cause of night sweating. According to the Nemours Foundation, drops in blood sugar that occur during sleep can cause someone to sweat during the night, and wake up with damp sheets and pajamas. This can also be accompanied by nightmares or grogginess and headache upon waking.

Neurological Conditions

Sweating is controlled by nerves, so night sweats can be a sign of some neurological disorders. The Mayo Clinic cites autonomic neuropathy and stroke can cause night sweating 3. Stroke can occur as the result of a burst blood vessel or a blood clot blocking the flow of blood to the brain. Autonomic neuropathy is a set of symptoms that occur when the nerves are damaged. Neuropathy is associated with diabetes, excessive alcohol use, Guillan Barre syndrome, Parkinson's disease, HIV, AIDS, anticholinergic medications and injury to the nerves caused by surgery or trauma.

Hormone Disorders

Several hormone disorders can cause night sweating. Pheochromocytoma is a rare adrenal gland tumor that produces norepinephrine and epinephrine. These hormones control blood pressure and heart rate, so increased production can cause increased heart rate, high blood pressure and night sweating. Hyperthyroidism, which is also known as overactive thyroid, can cause night sweats because too much thyroid hormone is produced by the thyroid gland. Carcinoid syndrome is rare but can cause night sweats because excess hormones are released by lung or intestinal tumors.