Night Sweats: Prevalence and Clinical Significance
Night sweats are a common symptom affecting approximately 10% to 60% of adults, with higher prevalence in specific populations such as menopausal women and those with certain medical conditions. 1, 2
Prevalence and Epidemiology
Night sweats (nocturnal hyperhidrosis) are a nonspecific symptom that many patients experience but may not spontaneously report to their healthcare providers. The prevalence varies significantly depending on the population studied:
- 10% among older primary care patients 2
- Up to 60% among women on obstetrics inpatient units 2
- Extremely common during menopause as part of vasomotor symptoms 3
Common Causes of Night Sweats
Hormonal Causes
- Menopause: The most frequent hormonal cause of night sweats 4
- Hyperthyroidism: Common endocrine cause of excessive sweating 4
- Hypogonadism: Less common but can cause night sweats in men, typically associated with sexual problems and low morning testosterone 4
Non-Hormonal Medical Conditions
- Gastroesophageal reflux disease (GERD) 1
- Obesity 1
- Obstructive sleep apnea 1, 5
- Mood disorders including anxiety and depression 1
- Infections: Particularly tuberculosis (though less common in modern practice) 5
- Malignancies: Especially lymphoma (though infrequently the cause in primary care settings) 5
- HIV infection 5
- Hypoglycemia 1
Medication-Related Causes
- Antihypertensives
- Antipyretics
- Selective serotonin reuptake inhibitors (SSRIs) 2
- Alcohol and substances of abuse 5
Diagnostic Approach
When a patient reports night sweats, a systematic approach is recommended:
Initial assessment: If a clinical diagnosis is apparent from history and physical examination, specific treatment for 4-8 weeks may be offered 1
Basic laboratory and imaging studies when cause is not apparent:
- Complete blood count
- Tuberculosis testing
- Thyroid-stimulating hormone level
- HIV testing
- C-reactive protein level
- Chest radiography 1
Additional selective testing based on clinical suspicion:
- CT of chest and/or abdomen
- Bone marrow biopsy
- Polysomnography
- Additional laboratory studies as indicated 1
Treatment Options
Treatment should be directed at the underlying cause when identified:
Menopausal symptoms: For severe vasomotor symptoms, nonhormonal treatments like venlafaxine, paroxetine, and gabapentin are effective in breast cancer survivors 3
Medication-induced night sweats: Alpha-adrenergic blockers may reduce night sweats in patients taking serotonin reuptake inhibitors 2
Primary sleep hyperhidrosis: Case reports suggest oxybutynin (an anticholinergic) may be effective for severe cases 6
Cancer-related night sweats: Thalidomide and thioridazine may benefit some terminal cancer patients 2
Prognosis
It's important to note that in primary care settings, the presence of night sweats alone does not appear to indicate an increased risk of death 1. Most patients reporting persistent night sweats do not have a serious underlying disorder 1.
Clinical Pearls
- Night sweats are often underreported unless specifically asked about by healthcare providers 4
- Distinguishing between isolated night sweats versus general excessive sweating can provide diagnostic clues 4
- Reports of night sweats should prompt questions about panic attacks and sleeping disorders 4
- If initial evaluation is normal and no specific cause is identified, reassurance and continued monitoring are appropriate 1