Excessive sweating that starts out of nowhere

A single episode can occur after exertion, a hot room, strong emotion, fever, alcohol or a medication change. Repeated episodes may relate to hormone or thyroid changes, glucose shifts, infection, sleep problems or a sweating disorder. Note whether the skin is generally damp or whether episodes arrive in waves, and whether they occur during sleep. Sweating is a symptom, so its pattern and accompanying signs guide the evaluation.

Move to a cooler place, loosen extra clothing and sip fluids if you are alert and able to drink. Write down the time, activity, food, medicines and symptoms around each episode. If you use glucose-lowering medicine, follow your personal plan for suspected low blood sugar rather than guessing. Do not stop regular medicine without medical advice. Arrange a review when episodes recur or have no clear trigger.

Seek urgent help when sudden sweating occurs with chest pain, breathlessness, fainting, confusion, severe weakness, one-sided symptoms or a fast irregular heartbeat. Get prompt care for sweating with high fever, repeated vomiting or signs of heat exhaustion. Hyperthyroidism, Hypoglycaemia and Excessive Sweating provide relevant background, but they cannot replace assessment of an acute episode.

What causes should be checked first? Could my medicines, glucose, thyroid or sleep symptoms be relevant? Should I keep a symptom diary or have tests during an episode?