Sleep hyperhidrosis, more commonly known as the night sweats, is the occurrence of excessive sweating (hyperhidrosis) during sleep. The sufferer may or may not also suffer from excessive perspiration while awake. A night sweat caused by a medical condition or infection can be described as ‘severe hot flashes occurring at night that can drench sleepwear and sheets, which are not related to an overheated environment’.  True night sweats with medical causes should be properly investigated by a medical physician.
Classification of Sweating
There are four types of sweats:
- Diaphoresis: Diaphoresis is a cold sweat. Diaphoresis is excessive sweating commonly associated with shock and other medical emergency conditions. It is distinguished from hyperhidrosis by the "clammy" or "cold state" state of the patient.
- Primary Hyperhidrosis: Primary hyperhidrosis is a condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature. This is not a cold sweat.
- Secondary Hyperhidrosis: Secondary hyperhidrosis is a condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature that is secondary to an underlying pathologic process such as infections, disorders of the thyroid or pituitary gland, diabetes mellitus, tumors, gout, menopause, certain drugs, or mercury poisoning. This is not a cold sweat.
- Night sweats: Sleep hyperhidrosis, more commonly known as the night sweats, is the occurrence of excessive sweating (hyperhidrosis) during sleep. The sufferer may or may not also suffer from excessive perspiration while awake.
Epidemiology and Demographics
Sleep hyperhidrosis may occur at any age, but is most commonly seen in early adulthood.
- No differences in men or women.
- Night sweats may occur for genetic reasons and may be relatively harmless.
Natural History, Complications and Prognosis
- The natural history is unpredictable. Some patients may have a self-limited course, where as some may experience sleep hydrosis for life.
- They can be distressing and disrupt sleep patterns if severe; the patient may be frequently awakened due to the discomfort of damp sleepwear.
- While some causes of night sweats, such as menopause, may be relatively harmless, night sweats may also be a sign of a serious underlying disease.
One of the most common causes of night sweats in women over 40 is the hormonal changes related to menopause and perimenopause. This is a normal part of menopause and while annoying, it is not necessarily dangerous or a sign of underlying disease. Some women experience night sweats during pregnancy due to hormonal changes.
While there can be many causes of excessive sweating at night including the menopause and, for example, a bedroom that is unusually hot or too many bed clothes on the bed, it is important to distinguish night sweats that arise due to medical causes from those that occur because the sleep environment is too warm.
Causes by Organ System
Causes in Alphabetical Order
- Abatacept Injection
- Adalimumab Injection
- Antidepressants (Bupropion, Selective serotonin reuptake inhibitors, Tricyclic antidepressants, Venlafaxine)
- Antipsychotics (e.g. Clozapine, Fluvoxamine, Phenothiazines)
- Antipyretics (e.g. Acetaminophen, NSAIDs, Salicylates)
- Anxiety disorder
- Autonomic dysreflexia
- Calcium channel blockers
- Camphoric acid
- Carcinoid syndrome
- Cerebral palsy
- Cholinergic agonists (e.g. Bethanechol, Pilocarpine)
- Cholinesterase inhibitors (e.g. Organophosphate pesticides)
- Chronic eosinophilic pneumonia
- Chronic fatigue syndrome
- Dental abscess
- Drug withdrawal: Benzodiazepines,Ethanol, Cocaine, Heroin and other opiates
- Eosinophilic pneumonia
- Familial dysautonomia
- Fungal infections (Blastomycosis, Coccidioidomycosis, Histoplasmosis)
- Gastroesophageal reflux disease
- Granulomatous disease
- Hodgkins disease
- Hormonal agents (e.g. GnRH agonist, Tamoxifen, Raloxifene, Flutamide)
- Oral hypoglycemic agents
- Hypothalamic lesions
- Idiopathic hyperhidrosis
- Infective endocarditis
- Infectious mononucleosis
- Kikuchi disease
- Lung abscess
- Lymphocytic leukocytosis
- Mycobacterium avium complex infection
- Oat cell carcinoma of the lung
- Obstructive sleep apnea
- Pentamidine inhalation
- Pneumocystis pneumonia
- Post-traumatic syringomyelia
- Premature ovarian failure
- Prinzmetal's angina
- Pyogenic abscess
- Relapsing fever
- Solid tumors
- Subacute endocarditis
- Substance abuse
- Sympathomimetic agents
- Systemic exertion intolerance disease
- Systemic mastocytosis syndrome
- Takayasu's arteritis
- Temporal arteritis
- Tricyclic antidepressants
- Urinary tract infection
- Waldenstrom's macroglobulinemia
History and Symptoms
- Medical history should focus on potential infectious and oncologic causes
- Social history should focus on substance abuse and travel
- Full exam with focus on endocrine, dermatologic and lymphatic systems
No specific features have been reported.
An echocardiogram can be obtained if there is a high suspicion of endocarditis
The folowing laboratory studies may be of use in determining the underlying cause of nightsweats.
More sophisticated laboratory studies would include the following:
- HIV w/ viral load
- Blood cultures
- Test for nocturnal hypoglycemia
- Free T4
- 5-hydroxyindoleacetic acid
- Quinizarin powder, turns purple on contact with sweat, can help in localizing the area of excessive sweating.
MRI and CT
- Suggest MRI/CT if necessary (chest/abdomen/pelvis)
A. The patient has has a complaint of excessive sweating during sleep.
B. Polysomnography with quinizarin powder dusted on affected areas is expected to demonstrate excessive sweating during sleep.
C. The primary complaint can be due to other medical disorders, such as febrile illness or diabetes insipid us.
D. Other sleep disorders (e.g., obstructive sleep apnea syndrome) may be present and can precipitate the disorder.
Minimal Criterion: A.
- Mild: No bathing or change of clothing is required; the patient may have to turn the pillow or remove blankets.
- Moderate: Sleep is disturbed by the need to arise and wash the face or other affected body areas, but no clothing change is necessary.
- Severe: A bath or change of clothing is required.
- Acute: 1 month or less.
- Subacute: More than 1 month but less than 6 months.
- Chronic: 6 months or longer.
Treat the underlying etiology with appropriate therapy
- Ibuprofen or acetaminophen
- Antimicrobial if infection is the cause
- American Academy of Sleep Medicine. International classification of sleep disorders, revised: Diagnostic and coding manual. Chicago, Illinois: American Academy of Sleep Medicine, 2001