Heat intolerance without sweating

Sweat normally evaporates from the skin and carries heat away. Reduced sweating can follow dehydration, certain medicines, skin or nerve problems, or a condition affecting sweat glands. Some people notice heat intolerance before they recognise that their skin stays dry. The pattern matters: consider whether sweating is absent everywhere or only in one area, whether it began recently, and whether fever, dizziness, headache, flushing, or a racing heartbeat occurs. This symptom does not identify a single condition.

Stop exertion, move to a cool place, loosen clothing, and use cool wet cloths or a fan. Sip fluids if you are alert and able to swallow, unless fluid intake has been restricted for another condition. Avoid strenuous heat exposure until the cause is clearer. Make a list of medicines and supplements, including products for allergies or bladder symptoms, and take it to a clinician; do not stop treatment on your own.

Call for urgent medical help if dry, overheated skin is accompanied by confusion, fainting, seizure, severe weakness, trouble breathing, chest pain, or repeated vomiting. Heat exhaustion can progress when the body cannot cool itself. Even without these signs, new or repeated inability to sweat warrants prompt medical review, particularly after a medicine change or illness.

Ask whether a medicine or health condition could reduce sweating, whether you need testing, and how to manage exercise, work, and outdoor exposure while symptoms continue.