Welding Allergy

Sweat allergy (also known as “cholinergic urticaria“) is not an allergy in the true sense of the word, as there is no reaction of the body’s own antibodies, i.e. the body’s defense system, to foreign substances. Rather, it is due to the lack of the ability to compensate for strong stimuli and shifts in the pH value into acid. It is therefore a so-called pseudoallergy, which also includes the sun allergy, for example. The fact that taking antiallergic medication can nevertheless help to alleviate the symptoms is due to the molecules released: these are similar or even the same in the case of a real allergy and a pseudoallergy.

Causes

Sweat is supposed to cool the skin during exertion, but as a side effect it also makes the skin surface acidic. The pH value of the skin is therefore lower. As a result, the skin is irritated over a large area – even if this is not noticed at first.

Since the irritation cannot be removed, the immune system responds by releasing inflammatory mediators. This reaction of the immune system always occurs when the body suspects an injury or a potentially injurious situation: the constant acidic irritation of the skin is also included. The release of the inflammation mediators takes place more precisely via the so-called mast cells.

These are activated and then release the corresponding messenger substances. As a result, the typical allergic signs appear, i.e. increased sensitivity to pain or itching, as well as overheating, redness and swelling due to the increased blood circulation. Important for the differentiation of the sweat allergy from a real allergy is the mechanism for activating the mast cells, which in this case is not caused by immune cells, but by an external physical stimulus. Here you can find more information on the topic: Itching of the skin – These are the causes

Diagnosis

For the diagnosis of allergies, the so-called prick test is usually used, in which allergens, which play a role in the allergic reaction, are applied to the skin and the skin surface is then slightly scratched to provoke a possible local reaction to the allergen. Since the “allergen” in cholinergic urticaria is the patient’s own sweat, a provocation test can only be performed by sweating, e.g. on a treadmill or similar. Often, however, a provocation test can be dispensed with in mild cases, as it has no effect on the usually symptomatic treatment.