Why do I get itchy skin when I sweat?

Get a rash when you sweat when working out? Then you could have a sweat allergy, says sports scientist Andy Blow...

Why do I get itchy skin when I sweat?

Sweat is known to trigger or exacerbate certain kinds of skin irritation, e.g. eczema or cholinergic urticaria (CholU, a type of hives brought on by exercise).


A sweat allergy can affect people at any age and appears as small red wheals that  become visible in response to an elevated body temperature. In many cases, the sweating can trigger intense itching, burning or stinging.

Two types of irritation are possible. One is that the irritation of damaged skin by the contamination or altered PH in sweat may result in itching and lesions. The other possibility is that there’s a hypersensitivity or mild allergy to the actual contents of the sweat.

How can you treat a sweat allergy?

To manage the symptoms, tannic acid has been found to suppress the allergic reaction, as has regularly showering and bathing. Broken or damaged skin often exacerbates the issue, so areas of skin abrasion caused by clothes rubbing, or similar, can make it worse.

A dermatologist can determine whether you have an allergy or not, so I’d recommend getting an appointment to investigate further.

Andy Blow is a Sports Scientist with a BSc Honours degree in Sports and Exercise Science from the University of Bath. An expert in hydration and nutrition, he has co-authored a number of scientific studies and books.

He was once the Team Sports Scientist for the Benetton and Renault Formula 1 teams and remains an adviser to the Porsche Human Performance Centre at Silverstone.

Andy has finished in the top-10 of Ironman and Ironman 70.3 races, as well as winning an XTERRA Age Group World title. It was his own struggles with cramp that led to him specialising in hydration and founding Precision Hydration.


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