What is aquagenic urticaria?

Aquagenic urticaria is a rare condition where skin contact with water causes a person to come out in a raised, itchy rash. Urticaria, otherwise known as hives, simply describes an allergic skin rash, which is itself a relatively common complaint. Aquagenic urticaria specifically refers to this reaction as a symptom of water allergy - and this is much more unusual.

People with aquagenic urticaria can be triggered by rain, snow, sweat and tears - water sources that most of us needn't worry about.

This allergic reaction doesn't appear to be affected by the temperature of the water, nor by how acidic or alkaline it is.

What happens when water touches your skin?

Within minutes you may develop:

• A skin rash or raised, red bumps.

• A burning sensation.

• Picazón.

What about drinking water?

In serious cases this might cause these side-effects:

• A rash around your mouth.

• Wheezing.

• Dificultad para tragar.

• Difficulty breathing/shortness of breath.

• Dolor de cabeza.

• Náuseas o fainting.

Symptoms tend to go away in 30 to 60 minutes. However, as water is so hard to avoid, self-care steps and treatment options are hugely important in improving a person's quality of life.

This allergy is so rare that there are fewer than 100 cases of aquagenic urticaria reported in medical literature¹.

From this small pool of data, we know that aquagenic urticaria affects more women than men. We also know that this condition often starts during puberty².

Aquagenic urticaria is as poorly understood as it is rare. However, research to determine the exact cause is ongoing, and there are a couple of popular theories:

Rather than an allergy to water itself, it may be chemicals in the water that act as allergens, triggering the immune system to release symptom-inducing histamines that attempt to fight the allergen.

The water may be interacting with naturally produced oils on the skin, known as sebum. An unusual interaction might produce a toxin that triggers the body to release histamine.

There's no cure for being allergic to water. Instead, the few people with this condition must try and limit their exposure to water, where possible, and take allergy treatments.

Tabletas antihistamínicas

This is a common treatment for many types of allergies, including fiebre del heno, that works by blocking the chain reaction that happens when your body releases histamine. Doctors usually recommend second-generation antihistamines, such as cetirizine and loratadine, as these don't cause drowsiness.

Skin barrier creams

These are applied directly onto skin, these can help to prevent water from seeping into skin and triggering an allergic reaction.

Steroid medication

This is used to dampen down the immune response and stop histamine release.

Allergy medicine

Omalizumab is an injection that acts against the antibodies produced by the immune system, to prevent symptoms from flaring up.

Ultraviolet light therapy

Also known as phototherapy, this has been known to work in some patients. It works by toughening the skin to make it less sensitive to water.

Epipens

These are for those who have severe reactions such as anafilaxia.

People with aquagenic urticaria have no problem with water inside their bodies - no one could live if their bodies rejected water internally.

This extremely rare condition is all about how water interacts with the skin. Completely avoiding exposure to water isn't possible, but being careful can help to make daily life easier:

Checking the weather forecast

Most people dislike getting caught in the rain, but for people with aquagenic urticaria, this can feel like falling into a bush of stinging nettles.

Taking brief, infrequent showers

Washing can't be completely avoided, but it's possible to shower less by substituting alcohol-based cleaners.

Managing sweat

Sheltering from extreme heat and avoiding sweat-inducing activities may help.

How do people with aquagenic urticaria eat and drink?

For most people with the condition, drinking water isn't an issue. However, some find that their lips and the inside of their mouth swells, itches, or burns - making drinking a necessary but painful daily experience.

The only ways to manage this is by relying on treatments and by avoiding foods that have a high-water content, such as tomatoes, cucumber, and watermelon.

1. Park et al: Aquagenic urticaria: a report of two cases.

2. Kai and Flohr: Aquagenic urticaria in twins.