Night Sweats

Night sweats is a common and usually harmless condition that is often associated with a higher temperature in bedroom. However, it may be also an unspecific symptom of certain serious diseases.


Banal causes

This category includes high temperature in the bedroom, thick blankets and lack of fresh air. Sleeping in aired room with opened window solves the problem.

Common infections

Common infections such as influenza are usually associated with sweating, people use take anti-inflammatory medications to quell fever. Night sweats usually disappear quickly after the infection withdraws.

Chronic infections

Some chronic infectious conditions are associated with recurrent night sweats. This includes potentially dangerous diseases such as infective endocarditis or tuberculosis. Night sweats also accompany some chronic viral infections such as AIDS.

Malignant diseases

Widespread cancers manifest among others by night sweats. That is a consequence of systemic inflammatory response to organism defense against tumor cells. Recurring night sweats are typical for "blood cancers" like leukemias and lymphomas. Anemia, fatigue and weight loss are other accompanying symptoms.


The decline of female sex hormones in menopause causes many symptoms including paroxysmal sweating.

Hormonal disorders

Overactive thyroid gland or pheochromocytoma is associated with bouts of sweating.


When a diabetic, who is treated with insulin or oral anti-diabetic drugs, wakes up sweaty, it may signify incoming hypoglycemic condition.

Idiopathic hyperhidrosis

This is a relatively rare condition, in which the patient sweats a lot without finding any underlying cause.

Diagnostic approach

It is very difficult to investigate symptom such as night sweats. Medical history and physical examination (especially search for enlarged lymph nodes) may be followed by blood samples to evaluate blood count, sedimentation rate and CRP level. At least basic imaging methods should be performed such as chest X-ray and abdominal ultrasound. Other diagnostic methods depend on current case, physician’s suspicion and outcome or previously mentioned diagnostic methods.

Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources