Night Sweats · What Are They, Causes, Treatment, and More

Published: Feb 04, 2025

Author: Lily Guo, MD•

Editor: Alyssa Haag, MD•

Editor: Ian Mannarino MD, MBA•

Editor: Kelsey LaFayette, DNP

Illustrator: Abbey Richard, MSc

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What are night sweats?

Night sweats, also known as sleep hyperhidrosis, refers to excess sweating while sleeping at night. The term describes abnormal sweating that is not related to an overheated sleeping environment (e.g., warm weather, wearing too much clothing, or using excess blankets). The amount of sweat produced is typically enough to soak through one’s clothes and bedding, often described as ‘drenching’. Night sweats are generally associated with an underlying medical condition, especially if it occurs consistently and interrupts sleep. An individual may seek medical evaluation for night sweats, especially if they are also experiencing other symptoms such as unintentional weight loss, fever, cough, pain, or diarrhea.

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What causes night sweats?

Night sweats may be associated with or caused by certain underlying medical conditions that cause fever or alterations in thermoregulation, like malignancy, infection, endocrine imbalance, or autoimmune disease. Examples of underlying medical conditions can include Hodgkin or non-Hodgkin lymphoma (i.e., cancers of the lymphatic system), which are the malignancies most associated with night sweats, though other cancers such as breast cancer and prostate cancer may cause one to experience night sweats through alterations in hormonal balance. During menopause, hormonal changes (e.g., a decrease in estrogen and progesterone) also make it more difficult to regulate body temperature which can lead to both hot flashes and sweating at night. Hyperthyroidism, caused by an overactive thyroid gland producing an excess of thyroid hormone, can cause night sweats. Infectious causes of night sweats most notably include tuberculosis, HIV/AIDS, endocarditis (i.e., an infection of the lining of the chambers and valves in the heart), osteomyelitis (i.e., a bone infection), and abscesses. Psychiatric disturbances, such as alcohol or drug use disorders, generalized anxiety disorder, post-traumatic stress disorder, or major depressive disorder may also cause night sweats due to an active sympathetic nervous system. Lastly, certain medications can cause night sweats including analgesics (e.g., nonsteroidal anti-inflammatory drugs such as ibuprofen); angiotensin II receptor blockers used to treat high blood pressure (e.g., valsartan, losartan); antidepressants (e.g., sertraline, venlafaxine); corticosteroids (e.g., prednisone); and antidiabetic medications (e.g., insulin, glipizide).

What are the signs and symptoms of night sweats?

The common symptom of night sweats is excessive sweating at night, often waking one up from sleep. The individual may describe their clothes and bedding as drenched in sweat. Depending on the cause of night sweats, there may be accompanying signs or symptoms. For example, those with underlying lymphoma may also experience unexplained weight loss; swollen lymph nodes that present as painless lumps, usually in the neck, armpit, or groin; fever; and generalized pruritus or itching. Breast cancer is associated with a lump or mass in the breast, or changes in appearance of the skin on the breast. If night sweats are due to underlying prostate cancer, other symptoms include difficulty urinating or frequent urination. Menopause signs and symptoms include cessation of menses and can lead to hot flashes, vaginal dryness, and mood changes. Lastly, those with infection may also have localized pain, fever, shivering/chills, persistent cough, generalized malaise, and weakness.

How are night sweats diagnosed?

Night sweats are often diagnosed based on a thorough review of the individual’s medical history including a review of medications and risk factors, and a physical examination. Certain components of the physical examination include obtaining vital signs to assess for fever which may raise the suspicion of an infectious or malignant cause, and palpating lymph nodes to check for enlargement. Laboratory tests are generally not used to diagnose night sweats, however they can help identify underlying causes. The tests ordered depend on what the healthcare provider believes to be the suspected underlying condition. Examples include blood tests, such as a complete blood count (CBC), comprehensive metabolic panel (CMP), or a Quantiferon assay for tuberculosis. If malignancy is suspected, imaging may be ordered including a computed tomography (CT) of the relevant body part (e.g., the chest or abdomen).

How are night sweats treated?

Treatment for night sweats depends on whether there is an identifiable underlying cause. If a comprehensive workup is done and no cause is identified, the symptoms may be treated by using air conditioning, wearing breathable, loose-fitting clothing made of cotton material at night, or using appropriate bedding. If night sweats are secondary to malignancy, treatment generally includes radiation therapy, chemotherapy, or surgery. If symptomatic, menopause can be treated with hormone therapy to replace estrogen. Hyperthyroidism can be treated with thyroid medications such as methimazole or propylthiouracil, or may require radioactive iodine treatment to decrease the number of thyroid cells producing excess thyroid hormone. Infections may require treatment with medications such as antibiotics (e.g., isoniazid, penicillin) or antiretrovirals. Cognitive behavioral therapy or antidepressants (e.g., fluoxetine, sertraline) may be used to control depression, PTSD, or generalized anxiety disorder. Lastly, if the night sweats are a side effect of medications, the medication list should be reviewed by a medical professional, and the offending agent may be discontinued or replaced with another medication with fewer side effects.

What are the most important facts to know about night sweats?

Night sweats refers to excessive sweating at night, not due to overheating from the sleep environment. Usually, the amount of sweat produced is enough to soak through clothes and bedding. Night sweats are a common symptom of certain underlying medical conditions, particularly if accompanied by weight loss, fever, or pain. Common causes include cancer, hormonal changes or endocrine disorders, infections, autoimmune diseases, psychiatric disturbances, and side effects from medications. The diagnosis of night sweats includes a thorough medical history, physical examination, and blood tests or imaging. Treatment depends on the underlying cause and may include changing one’s sleep environment.

References

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Gaddey HL, Riegel AM. Unexplained lymphadenopathy: Evaluation and differential diagnosis. Am Fam Physician. 2016;94(11):896-903. https://www.aafp.org/afp/2016/1201/p896.html

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Mold JW, Holtzclaw BJ. Selective serotonin reuptake inhibitors and night sweats in a primary care population. Drugs Real World Outcomes. 2015;2(1):29-33.