Why does hyperhidrosis happen?

Primary hyperhidrosis often affects specific areas such as the palms, soles, underarms, or face, and may run in families. The sweating can happen while you are awake even when the surroundings are cool. Secondary sweating is linked to a medicine or an underlying condition and may affect larger areas, including the whole body. A clinician may ask when it began, which areas are involved, whether it occurs during sleep, and what medicines or supplements you take.

Wet skin can soften and irritate the surface, allowing problems such as heat rash or intertrigo to develop. Foot moisture can also make fungal-looking changes worth checking rather than assuming the sweating itself is the only issue. Read about [Excessive Sweating](/symptoms/excessive-sweating/) as a related symptom.

Keep a brief diary of triggers, timing, body areas, night symptoms, and recent medicine changes. Use breathable clothing, change damp socks, and dry skin folds and feet carefully. A healthcare professional can review possible causes and discuss options such as prescription antiperspirant, iontophoresis, botulinum toxin injections, or microwave sweat gland treatment. The suitable choice depends on the location, severity, skin condition, and whether a cause needs treatment first.

Arrange a medical assessment if sweating is new, widespread, occurs during sleep, or is disrupting work, sleep, movement, or social activities. Seek urgent help for heavy sweating with chest discomfort, fainting, confusion, severe breathlessness, or signs of heat illness. Sudden sweating with shaking or weakness also deserves prompt attention, particularly if you have diabetes or take medicines that affect blood sugar.

Could a medicine or health condition be contributing? Does my distribution suggest primary or secondary hyperhidrosis? Which treatment fits my affected areas, and how should irritated skin be protected?