What Are Night Sweats a Sign of?

Night sweats may result from fever or infection, hormonal problems or menopause, among other causes.

Night sweats (sleep hyperhidrosis) are episodes of excessive perspiration that occur when you are sleeping. The sweating can range from moderate perspiration to drenching sweats that soak through clothing and sheets. 

Hot flashes, which are sudden feelings of warmth, can occur any time. When they occur at night, they are considered night sweats. 

Night sweats are not the same as overheating, such as that due to a warm bedroom or a heavy blanket.

Night sweats are characterized by moderate to drenching sweating at night. They are a sign of many different conditions.

What Causes Night Sweats? 

There are many causes of night sweats, including: 

• Menopause/perimenopause
• Hot flashes/night sweats are considered a hallmark symptom of perimenopause and menopause
• Certain medications
• Selective serotonin reuptake inhibitor (SSRI) antidepressants
• Steroids
• Fever reducers, such as aspirin or acetaminophen
• Caffeine 
• Alcohol and drug use 
• Cholinergic agonists (such as pilocarpine and bethanechol)
• Diabetes medications
• Estrogen/androgen modulating agents 
• Methadone
• Albuterol and other sympathomimetics
• Cyclosporine
• Withdrawal from alcohol, opioids, and cocaine
• Infections
• Tuberculosis
• Bacterial infections
• Fungal infections
• Human immunodeficiency virus (HIV)
• Malaria
• Hormone Problems
• Overactive thyroid (hyperthyroidism)
• Diabetes and high blood sugar
• Abnormal levels of sex hormones
• Hypothalamic dysfunction
• Adrenal gland tumor (pheochromocytoma) 
• Carcinoid syndrome (slow-growing tumors that produce hormones)
• Insulinoma 
• Acromegaly 
• Other Causes of Night Sweats
  • Neurologic causes
    • Autonomic dysreflexia
  • Posttraumatic or idiopathic syringomyelia
  • Sleep disorders 
  • Pregnancy and the post-partum period
  • Anxiety and panic attacks 
  • Hyperhidrosis (excessive sweating) that may affect people during both day and night
  • Gastroesophageal reflux disease (GERD)
  • Temporal arteritis
  • Sarcoidosis
  • Myalgic encephalomyelitis/chronic fatigue syndrome 
  • Certain types of cancer 
    • Lymphoma (Hodgkin and non-Hodgkin) 
    • Prostate cancer
    • Renal cell cancer
    • Germ cell tumors
    • Advanced medullary carcinoma of the thyroid 
  • Side effect of cancer treatments
    • Hormone therapy for women with breast cancer and men with prostate cancer
    • Surgery
    • Radiation therapy
    • Chemotherapy 

The cause of night sweats is diagnosed with a patient history and physical examination. Depending on the suspected cause, testing to determine the cause may include: 

• Blood tests
  • Complete blood count (CBC)
  • Thyroid tests 
  • Follicle-stimulating hormone (FSH)
  • HIV testing
  • C-reactive protein
  • Liver function tests
  • Blood cultures
  • Interferon gamma release assay
  • Pregnancy
• Tuberculosis skin test
• Urine testing
  • Urinalysis
  • 24-hour urine collection
• Thoracic echocardiogram
• Chest X-ray
• Computerized tomography (CT) scan of the chest, abdomen, pelvis
• Bone marrow biopsy

Treatment for night sweats varies depending on the cause. Treatments may include: 

• Environment and lifestyle changes
  • Keep the thermostat at a lower temperature 
  • Use lighter bedding 
  • Get a more breathable mattress and sheets
  • Wear lightweight, loose-fitting bedclothes    
  • Avoid caffeine, alcohol, and spicy foods, especially in the evening    
  • Drink cold water before going to bed    
  • Lose weight if overweight/maintain a healthy weight
  • Relaxation techniques
• Cognitive behavioral therapy (CBT) 
  • Talk therapy based on reframing negative thoughts in order to promote healthier actions
• Modifying medications
  • If certain medications cause night sweats: change the prescription, dosage, or regimen
    • Never stop taking a prescribed medication or change the dose or regimen without first talking to your doctor
  • If the night sweats are caused by an underlying infection or hormone problem, medication may help treat them