Exploring Aquagenetic Urticaria - The 'Water Allergy'

Lilly Scholz
Dec 17, 2025
3 min read

When people think of allergies, they tend to imagine hayfever, peanut butter or certain medications. An allergy to water however, is probably not the first thing that comes to mind…

What is Aquagenic Urticaria?

Aquagenic urticaria, also known as the ‘water allergy’, is a rare skin condition in which red, itchy hives, as seen above, are triggered after exposure to water. ‘Urticaria’ is the medical term for hives, with ‘Aqua’ being the latin word for water. However while urticaria affects around one-fifth of the entire population at some point in their life, there are only 50 known cases of this so-called ‘allergy’ in medical history dating back to 1964.

While aquagenic urticaria may occur in adults and children of any gender, it is more commonly seen in females during or after puberty.

The famous case of Rachel Warwick led her to soon become known as ‘The Woman Who is Allergic to Water’. In her world, a simple bath becomes a nightmare, and swimming in tropical oceans is as awful as using bleach on your skin. Even the slightest touch of water, including snow, sweat or tears, causes Rachel to develop extremely itchy rashes that can persist for hours on end.

What are the causes?

Aquagenic urticaria, although commonly mistaken for an allergy, is not in fact one. Typical allergies involve the body producing antibodies against a specific allergen. In the case of aquagenic urticaria, the reaction is thought to happen through reacting with other substances in/on the skin, triggering mast cells to release histamine. Therefore, the exact cause of aquagenic urticaria is unknown; however, there are a few theories:

An allergen or chemical in the water, rather than the water itself
Water interacting with substances on the skin
Chemical additives in water such as chlorine

What are the symptoms of it?

Key symptoms that those with aquagenic urticaria could experience are as followed:

Urticaria (hives) within 30 minutes of exposure to water
Burning pain
Itchiness
Redness and inflammation
Wheezing and rapid, shallow breathing
Headache
Dizziness

In more detail, the rash you get with aquagenic urticaria might appear as small, raised bumps, tending to be itchy and sometimes painful. Moreover, they usually appear on your neck, upper arms and trunk. While all these symptoms might sound extreme, they tend to resolve within 30-60 minutes after you limit your contact with water. However, in very rare cases aquagenic urticaria could cause anaphylactic shock, requiring immediate medical treatment with epinephrine.

What is the diagnosis?

In order to diagnose aquagenic urticaria, doctors will perform a physical exam followed by a medical history review. Most commonly called the ‘water challenge test’ or ‘water provocation test’, doctors place a warm (35*C) and damp cloth on your skin for about 20 minutes. They will then check to see if you develop any symptoms such as hives. Typically, this diagnosis is performed on the upper half of your body since symptoms are more common in that region, and the temperature of the water helps to rule out varieties such as heat-induced or cold-induced urticaria.

What are the treatments?

At the moment, there is no known cure for aquagenic urticaria yet. While it is not pragmatic, the most effective approach would be to completely avoid water. However, since aquagenic urticaria can also be caused by sweat, tears, rain or snow, avoiding water at all is not exactly ideal.

Instead doctors might recommend:

Antihistamines: Typically the first line of treatment, used to reduce itching, pain and swelling.
Topical medications: Creams can help form a barrier between the skin and water, avoiding the formation of hives.
Phototherapy: This involves the usage of artificial UV light and might be considered if antihistamines and topical medications are not effective. UV therapy toughens the skin, and makes it less sensitive to water.

What you can take away from this article is that although there is no cure for this extremely rare condition, appropriate treatment and lifestyle changes can minimize the challenges faced when dealing with aquagenic urticaria.