Mayo Clinic experts state that excessive sweating (hyperhidrosis) occurs when the sweat glands produce more perspiration than necessary to cool the body 12. In some cases, this may be the side-effect of taking certain medications. But there are also specific medical conditions that can cause excessive sweating. The Mayo Clinic cautions that excessive sweating can be a symptom of many physical conditions, so always see a doctor to address specific concerns 1.

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If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Conditions Affecting the Heart

Excessive sweating—specifically night sweats—can be a symptom of endocarditis, in which bacteria or germs spread from another part of your body to damaged parts of the heart. This can result in life-threatening complications when left untreated, the Mayo Clinic notes.

A heart attack, which occurs when a blood clot obstructs blood flow through a major vessel that delivers blood to the heart, can also cause excessive sweating. Other symptoms include a pain that endures for more than a few minutes that may radiate beyond the chest to the shoulder, back, arm, and even the teeth and jaw. Other symptoms can include faintness, nausea and shortness of breath, the Mayo Clinic reports.

Anxiety Disorders

Normal sweating occurs during times of emotional duress, such as stress or embarrassment. Generalized anxiety disorder can also cause excessive sweating, the Mayo Clinic says 1. Anxiety disorders, which may affect relationships and interfere with daily life, have other symptoms. These can include diarrhea, nausea, difficulty concentrating or sleeping, feeling "on edge" and obsessive worrying.

Certain Cancers

Non-Hodgkin lymphoma and leukemia can also cause symptoms of excessive sweating, according to Mayo Clinic experts 1. Excessive sweating usually occurs at night, the Mayo Clinic notes 1.

Non-Hodgkin lymphoma, a cancer that starts in the lymphatic system, may have no other symptoms than swollen lymph nodes in the neck, armpit or groin in its first stages.

Thyroid Disease

The medical condition of hyperthyroidism (the most common cause of which is the autoimmune disorder Graves' Disease) can also cause excessive sweating. Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone, which affects the body's metabolism.

Infectious Diseases

Tuberculosis, or TB, generally affects the lungs and is spread when someone contracts the airborne bacteria through exposure to a person with the disease. The Mayo Clinic notes that most people who acquire the bacteria don't show symptoms of TB.

Other Causes

Excessive sweating may not be the result of a physical malady, but a symptom of stress, hot flashes during menopause, or the side-effect of taking certain medications (such as:

  • beta blockers
  • tricyclic antidepressants)
  • Mayo Clinic experts note 1

But excessive sweating can also have no underlying cause. This type of sweating, known as focal hyperhidrosis, typically begins before the age of 20 and occurs mainly during the day, subsiding at night 2. Focal hyperhidrosis is suspected to have a genetic component, the Mayo Clinic reports 2.