What are the causes of night sweats?

Causes of Night Sweats

Night sweats can be caused by a wide range of conditions from benign to life-threatening, with tuberculosis, lymphoma, and other malignancies being the most serious underlying causes that require prompt evaluation. 1

Common Causes of Night Sweats

Infections

• Tuberculosis (TB): A classic cause of night sweats, particularly when accompanied by cough, weight loss, and fever 2
• HIV infection: Should be considered in patients with risk factors and unexplained night sweats 1
• Other infections: Various bacterial, viral, and fungal infections can cause night sweats

Malignancies

• Lymphomas: Particularly Hodgkin's and non-Hodgkin's lymphoma, often accompanied by lymphadenopathy and weight loss 1
• Solid organ cancers: Various malignancies can present with night sweats as part of B symptoms 1
• Hematologic malignancies: Consider when night sweats occur with lymphadenopathy, weight loss, and fever 1

Endocrine Disorders

• Hyperthyroidism: Can cause increased sweating, including night sweats 3, 4
• Hypoglycemia: Nocturnal hypoglycemia can trigger night sweats 5
• Menopause: One of the most common causes of night sweats in middle-aged women 2, 4
• Male hypogonadism: Less common but should be considered in aging males with sexual dysfunction 4

Medication-Related

• Antidepressants: Particularly selective serotonin reuptake inhibitors (SSRIs) 6
• Antihypertensives: Can cause night sweats as a side effect 5
• Antipyretics: Paradoxical sweating with medication withdrawal 5
• Hormone therapies: Including those used in breast cancer treatment 2

Sleep Disorders

• Obstructive sleep apnea (OSA): Consider when night sweats are accompanied by snoring, witnessed apneas, or daytime sleepiness 1, 3
• Other sleep disorders: Various parasomnias can be associated with night sweats 1

Gastrointestinal Disorders

• Gastroesophageal reflux disease (GERD): Often overlooked cause of night sweats 3, 7

Other Causes

• Mood disorders: Anxiety, panic attacks, and depression can manifest with night sweats 3
• Obesity: Associated with increased sweating, including at night 3
• Substance use: Alcohol and drugs like heroin can cause night sweats 5
• Atopic dermatitis: Particularly in children 1

Diagnostic Approach

Initial Evaluation

1. Focused History:

   • Duration, frequency, and severity of night sweats
   • Associated symptoms (fever, weight loss, cough, lymphadenopathy)
   • Medication review
   • Substance use history
   • Sleep patterns and symptoms of sleep disorders

2. Physical Examination:

   • Vital signs including temperature
   • Lymph node examination
   • Thyroid examination
   • Lung examination
   • Skin assessment

3. Basic Laboratory Testing:

   • Complete blood count (CBC) 1, 5, 3
   • Thyroid-stimulating hormone (TSH) 1, 5, 3
   • Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) 1, 5
   • HIV testing 1, 5, 3
   • Tuberculosis testing (PPD or interferon-gamma release assay) 1, 5

4. Initial Imaging:

   • Chest radiograph to evaluate for TB, lymphoma, or other malignancies 1, 5, 3

Additional Testing Based on Initial Findings

• If respiratory symptoms or TB risk factors: XpertMTB/RIF testing when available 2
• If suspicion for malignancy: Consider CT scans of chest/abdomen and possibly bone marrow biopsy 5, 3
• If sleep disorder suspected: Consider polysomnography 1
• If endocrine disorder suspected: Additional hormone testing as appropriate

Management Approach

1. If a specific cause is identified: Treat the underlying condition

   • For TB: Appropriate anti-tuberculosis therapy
   • For malignancies: Referral to oncology
   • For hyperthyroidism: Anti-thyroid medications
   • For menopause: Consider appropriate symptom management
   • For GERD: Anti-reflux treatment 7
   • For medication-induced: Consider medication adjustment

2. If no specific cause is identified after initial evaluation:

   • Reassurance that night sweats alone do not indicate increased mortality risk 3
   • Symptomatic management with improved sleep hygiene
   • Periodic reassessment if symptoms persist or change

Important Considerations and Pitfalls

• Don't miss TB in high-risk populations: Consider testing regardless of cough duration 2, 1
• B symptoms: The combination of night sweats, weight loss, and fever should raise concern for lymphoma or other malignancies 1
• Medication review: Always perform a thorough medication review as many medications can cause night sweats 5
• Reassurance when appropriate: Most patients with night sweats in primary care settings do not have a serious underlying condition 3, 6
• Consider GERD: Often overlooked as a cause of night sweats 7

Night sweats are a common symptom that can range from benign to serious causes. A systematic approach to diagnosis focusing on the most likely causes based on accompanying symptoms and risk factors will lead to appropriate management in most cases.