Hyperhidrosis is a medical condition that causes excessive sweating (perspiration). It usually affects the armpits, hands or feet. However, most areas of the skin’s surface can be affected.

Sweating helps maintain body temperature, skin hydration and fluid and electrolyte balance. People sweat in response to numerous factors (e.g., warm temperatures, physical exertion, anxiety). However, individuals with hyperhidrosis sweat excessively, even when these triggers are not present (e.g., in cool temperatures, during periods of rest).

Primary hyperhidrosis is a chronic (ongoing) condition that is associated with overactive sweat glands. Secondary hyperhidrosis occurs in response to a separate medical condition (e.g., overproduction of thyroid hormones [hyperthyroidism]). Hyperhidrosis can be further classified according to its cause and/or location. For example, excessive sweating caused by the hypothalamus region of the brain, which regulates body temperature, is called hypothalamic hyperhidrosis.

Visible signs of hyperhidrosis are often obvious and may include underarm stains, dripping palms or wet clothing. Diagnosis of hyperhidrosis is often based on the patient’s symptoms and medical history. If secondary hyperhidrosis is suspected, additional testing (e.g., x-ray, urinalysis) may be performed to identify or rule out any potential underlying conditions.

Secondary hyperhidrosis may cease if its underlying cause is identified and successfully treated. Treatment of primary hyperhydrosis focuses on symptom relief and may include use of antiperspirants, surgery or medications.