Aquagenic urticaria

Aquagenic urticaria (or water allergy) is a rare physical urticaria caused by contact with water. This contact causes the appearance of welts or hives and a lot of itching. In some cases it can affect the mucous membranes causing difficulty in swallowing or breathing. Its cause is unknown and it is one of the most infrequent and disabling hives, since it hinders daily activities such as bathing or drinking fluids.

• It causes hives that swell within minutes to hours of contact with water and cannot be studied by common allergy tests.
• It can occur even when drinking fluids, causing inflammation of the windpipe and making it difficult to swallow or breathe.
• There are medications that can slow down or mitigate the reaction, although none can eliminate it.

Who does it affect and what symptoms does it cause?

It generally affects young people, more frequently women than men. There is no way to predict or avoid it, as its cause is currently unknown.

In contact with water, both cold and hot, or sweet or salty, the patient notices pain, itching on the skin and the appearance of red bumps that swell after a few minutes. The episodes can persist for minutes or hours. They can occur with rain, bathing, sweating, or even drinking fluids, causing inflammation of the glottis or trachea with difficulties in swallowing or breathing. These situations represent a vital emergency and are very distressing.

Are allergy tests useful in this case?

Although this disease is popularly known as “water allergy”, it cannot be studied by common allergy tests, but by a provocation test, which is performed by wetting the patient's skin with fresh or salt water, and at different temperatures. As many times the disease can be combined with other physical urticarias, it is usually tested if the patient also has pressure or cold urticaria. blood tests do not usually show any alteration in aquatic urticaria.

How is it treated?

There is no effective treatment, but various medications can slow down or mitigate the reaction. These include antihistamines, corticosteroids, stanazolol, or omalizumab. It is convenient for the patient to be studied by a dermatology service, preferably at a third-level center, because they usually have more experience and have access to clinical trials with new treatments. Patients susceptible to severe seizures should always carry an epinephrine injectable along with instructions for administering it in the event of an episode and no emergency department nearby. Remember that if you have any symptoms, you can access the 24-hour Medical Guidance service where they will answer any questions about your health.