Water has been universally acknowledged as the substance of life, something which we all rely upon to survive. But what happens when this life-sustaining substance induces chronic allergic reactions and pain? Aquagenic Urticaria (AU) is an allergic reaction to water characterized by the rapid development of hives¹. AU differs from cholinergic urticaria in that reactions occur even if the person is not exercising in water, and regardless of water temperature. Being an ultra-rare disorder with approximately 100 reported cases in literature as of November 2020¹, AU has received little attention from the scientific community. While there has been a female prominence over males, genetics surrounding aquagenic urticaria are largely unknown with no known inheritance pattern. Ignorance surrounding AU in the scientific community, as with other rare diseases, has led to great misunderstanding and stigma surrounding the condition.

“It was hard [to diagnose] because the ocean was really painful but sitting at home in the summer was also painful and skiing in the winter was painful too”

Tessa, the face behind the advocacy Instagram account @livingwaterless, first started showing symptoms at age 8. “It was hard [to diagnose] because the ocean was really painful but sitting at home in the summer was also painful and skiing in the winter was painful too”. Without a clear indication of what caused her reactions, it took an additional two years of research for her to be diagnosed with aquagenic urticaria. The diagnostic progress relies upon a supportive clinical history and conformational water provocation tests². The most common confirmation test for AU is to apply a wet cloth to the skin for 20 minutes while under observation. While AU is specific to contact with water, it can present similarly to cholinergic urticaria (CholU). Reactions related to CholU occur due to the accumulation of sweat from exercise, warm bathing, and/or emotional stress³. Patients with CholU have reported different sensations associated with hives, such as a stinging or tingling pain rather than itching. Provocation tests to rule out other types of urticaria center around the idea of raising one’s body temperature and monitoring for related reactions. This can be done by having the individual exercise or sit in a warm bath, but in this circumstance, the use of water is unrelated to the purpose of provocation tests for AU. Even once a diagnosis of urticaria is being investigated, there is a diagnostic challenge in differentiating AU from other types of urticaria which result in similar lesions. Additionally, there are further clinical subtypes of aquagenic urticaria that must be considered during the diagnostic process. Salt-dependent AU is specific to seawater but not tap-water, whereas aquagenic pruritus results in the severe itching of the skin without lesions⁴.

The progression of symptoms can vary with each case, but for Tessa, her symptoms have generally progressed every 3-4 years. When this happens, the constant sores around her mouth and on her scalp worsen, becoming inflamed and infected. During this period, the time it takes for a reaction to occur is lessened and medication is unable to compensate resulting in more extreme reactions. The progression phase is also marked with the onset of additional symptoms, so for many individuals with AU the condition worsens with age.

As with other allergies, antihistamines, which inhibit the physiological effects of histamine, can initially be effective in reducing allergic responses. However, as time goes on they become less effective as the disease progresses and worsens. Management can also involve scopolamine, a common medication used in surgery to decrease saliva, and barrier creams⁵. Ultimately, the best tactic to reduce reactions to water is for individuals with AU to avoid unnecessary exposure. This preventative measurement means limiting time spent in the sun and reducing physical activity to avoid reactions triggered by sweat. It also calls for a different approach to personal hygiene, by showering infrequently and taking additional precautions when brushing teeth.

Internal reactions are also a possibility with aquagenic urticaria, though not all cases present as such. To trick her body into accepting water to stay hydrated, Tessa consumes whole milk from an animal rather than water on its own. In this way, the fats and proteins surround the water molecules and act as a buffer. Drinking approximately 30 ounces of whole milk a day leaves Tessa chronically dehydrated but allows her body to take in enough water without having extreme reactions. Similar to physical reactions, for those who react internally, it is best to avoid foods with high water content such as some vegetables and fruit. Tessa has constant sores inside her mouth because she cannot avoid water in some foods and from daily activities such as brushing her teeth.

**Figure 1: Searches of “aquagenic urticaria” over the past 10 years, note the high of 12 searches in April of 2019**

**Figure 2: Comparison with searches of “urticaria” which has increased slightly over the past 10 years**

Aquagenic urticaria remains a largely undiscussed condition, as demonstrated by the low number of google searches over the past 10 years and the general misunderstanding of the public (Figure 1, 2). The lack of knowledge surrounding specific types of urticaria impacts the diagnostic process and the quality of treatment available to individuals. Additionally, existing resources are limited to scientific articles that are less accessible to the general public—further contributing to the stigmatization of rare diseases such as aquagenic urticaria.

Tessa originally started her Instagram account as a way to easily update and educate the people in her life. Out of a need for more resources on AU, her account has become a space to answer questions and have important conversations regarding disability, mental health, and the trials of everyday life. Through the platform, she has also been able to connect users with aquagenic urticaria through creating group chats. Her efforts have fostered a supportive online community and spread awareness for aquagenic urticaria.

You can find Tessa’s account at: https://www.instagram.com/livingwaterless/?hl=en

Mya E. George

References
1. Robles‐Tenorio, A., Tarango‐Martinez, V. M., & Sierra‐Silva, G. Aquagenic Urticaria: WATER, friend, or foe? Clinical Case Reports. https://doi.org/10.1002/ccr3.2880. Published September 24, 2020.
2. Rothbaum, R., & McGee, J. Aquagenic Urticaria: Diagnostic and management challenges. Journal of Asthma and Allergy.
https://doi.org/10.2147/jaa.s91505. Published November 29, 2016. 3. Fukunaga, A., Washio, K., Hatakeyama, M., Oda, Y., Ogura, K., Horikawa, T., & Nishigori, C. Cholinergic urticaria: Epidemiology, physiopathology, new categorization, and management. Clinical Autonomic Research. https://doi.org/10.1007/s10286-017-0418-6. Published April 5, 2017.
4. Steinman, H. K., & Greaves, M. W. Aquagenic pruritus. Journal of the American Academy of Dermatology. https://doi.org/10.1016/s0190-9622(85)70149-1. Published July 1, 1985.
5. Polcari, M. M162 AQUAGENIC URTICARIA in an adolescent female. Annals of Allergy, Asthma & Immunology. https://doi.org/10.1016/j.anai.2019.08.162. Published November 1, 2019.

Cite This Article:

George M., Carmona A. & Mughal R. Aquagenic Urticaria: An Absolutely Unavoidable Allergy. Illustrated by S. Montakhaby. Rare Disease Review. September 2021.