What are the other Names for this Condition? (Also known as/Synonyms)

• AU (Aquagenic Urticaria)
• Water Allergy
• Water Urticaria

What is Aquagenic Urticaria? (Definition/Background Information)

• Urticaria is a common inflammatory condition of skin that results in weals (red skin sign with itching) and/or angioedema (swelling due to fluid accumulation). It is seen in individuals of a wide age group and may be described as acute or chronic, based on the duration of the signs and symptoms
• Aquagenic Urticaria (AU) is a very rare type of urticaria in which hives (urticaria) develop following exposure of skin to water. The exposure may be of any form - during swimming, while walking in the rain, washing one’s hands, or taking a shower
• Aquagenic Urticaria forms a subset of chronic inducible urticaria, a form of chronic urticaria, in which the signs and symptoms usually occur within a few minutes of exposure to the stimuli (or a known trigger)
• The condition is also known as Water Urticaria and is more common in women. The water may be of any temperature (whether hot, warm, or cold) and from any source (kitchen tap water, pool water, or river water), and the skin rashes appear almost within minutes of exposure
• On contact with water, tiny red or white weals form on the exposed surfaces (face, neck, or arms). It may or may not present itching. Also, typically angioedema is not reported in Aquagenic Urticaria
• The condition is treated symptomatically, when required. The treatment may involve the use of phototherapy, antihistamines, and immunosuppressive medication, in case of severe signs and symptoms
• In many individuals, Aquagenic Urticaria is a short-term duration skin condition that is known to get better on its own without any treatment, usually within an hour. However, it may recur following exposure of skin to water

Who gets Aquagenic Urticaria? (Age and Sex Distribution)

• Aquagenic Urticaria is a very rare condition. Only a few (over 100) cases have been reported worldwide
• This skin condition can affect both children and adults, though it is more often seen in adults
• Even though males and females are affected, it is a lot more common in females (after puberty)
• There is no race or ethnic preference observed

What are the Risk Factors for Aquagenic Urticaria? (Predisposing Factors)

The main risk factor for Aquagenic Urticaria is contact with water that is from any source and at any temperature. This may occur following:

• Swimming in pools, rivers, lakes, or seas
• Showering or taking a bath
• Washing one’s hands
• Exposure to rain

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Aquagenic Urticaria? (Etiology)

Urticaria can be caused by a variety of factors. The condition develops due to the release of chemical substances, such as histamines, platelet activating factor, and cytokines (example bradykinin), from inflammatory cells called mast cells and basophils.

• Aquagenic Urticaria is a form of physical urticaria that occurs following a known trigger, which is contact with water in this case. Nevertheless, the exact reason for development of this type of skin condition is not well-understood
• Researchers believe that the cause may be due to the presence of an unknown substance in skin that reacts with water to cause the hives
• Alternatively, researchers think that it may be due to an unknown substance that is dissolved in water triggering an adverse reaction following contact with the skin (skin sensitivity to certain dissolved water compounds)
• The temperature, source, and type of water (such as drinking water, seawater, or chlorinated water) does not seem to have a bearing on the cause of Aquagenic Urticaria

Most cases are known to occur randomly (sporadically); although, very infrequently, a family history of the condition has been reported in the medical literature.

What are the Signs and Symptoms of Aquagenic Urticaria?

The signs and symptoms of Aquagenic Urticaria may be mild or severe, localized or diffused, and can vary from one individual to another. The signs and symptoms of Aquagenic Urticaria that occur within a few minutes (10-15 minutes, and sometimes after 30 minutes) of exposure to water may include the following:

• Formation of skin rashes or weals (wheals, urticaria, hives) that are associated with redness (or pinkish discoloration) and itching, in some cases
• The skin surrounding the affected area (weal) may be normal skin color or appear red (erythema)
• The weals usually appear at the skin site of contact with water and may be of any shape and size; the condition can be localized or widespread
• The common parts of the body affected include the face and neck, shoulders and torso, including the arms/hands
• In some individuals, there may be a burning sensation accompanying itching
• Individual weals are tiny to small and range in size from 1-3 mm; but, numerous weals covering a large area of the body skin may be observed
• The weals may last anywhere from 10 minutes to 120 minutes; but most recede within 30-60 minutes, following removal of trigger (or water source)
• In some cases, it can lead to hyperpigmentation (increased skin pigmentation) or hypopigmentation (decreased skin pigmentation)
• When pressure is applied on the affected area of skin, it blanches (becomes pale or white in color)
• Scratching can result in worsening of the symptoms and may lead to further skin complications such as ulceration and secondary infections
• Pain, pain on touch, in some cases
• Angioedema is generally not noted with Aquagenic Urticaria

Other parts of the body are generally not affected and are rare (i.e., absence of systemic symptoms). Individuals, may have other forms of inducible (physical) urticaria such as cholinergic urticaria.

How is Aquagenic Urticaria Diagnosed?

A diagnosis of Aquagenic Urticaria may involve the following tests and examinations:

• Physical examination of  the skin and medical history evaluation
• Skin allergy test
• Radioallergosorbent (RAS) test; to determine the specific allergy-causing substance
• Water challenge test, which is a specific test undertaken for Aquagenic Urticaria
• Tests to exclude other forms of physical/inducible urticaria
• Blood test to detect various antibodies against allergens including:
  • Complete blood count (CBC) including eosinophil count since, there may be increased number of eosinophils (peripheral eosinophilia)
  • Antinuclear antibody (ANA) test
  • Erythrocyte sedimentation rate (ESR) test
  • Immunoglobulin E (IgE) levels in blood
  • Serum level of complement
  • Serum C-reactive protein blood test
• Tests to rule-out other underlying autoimmune conditions and infections (if necessary)
• Skin biopsy (if necessary): A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis
• A differential diagnosis may be considered to eliminate certain skin conditions, prior to arriving at a definitive diagnosis

Note: The healthcare provider may induce symptoms by administering the triggers in a controlled fashion. This procedure is performed under close medical supervision, either in an out-patient healthcare setting, or as an in-patient setting in a hospital. Since, potentially life-threatening symptoms may develop during this procedure, access to emergency medical resources is generally warranted. Hence, such testing should not be performed at home.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Aquagenic Urticaria?

The following complications of Aquagenic Urticaria may be noted:

• Severe stress from allergy to water
• Intense scratching may result in skin scarring
• Itching can lead to ulceration of skin, causing superimposed bacterial and fungal skin infections
• Cosmetic concerns leading to stress
• Frequent episodes of urticaria can affect the quality of life, which can result in severe stress. This severe stress can in-turn be a trigger for further worsening of the condition

How is Aquagenic Urticaria Treated?

The treatment depends upon the severity of the signs and symptoms of Aquagenic Urticaria. In severe cases, an allergy specialist may be consulted. The treatment measures may include:

• Topical steroid treatment that may include moisturizing creams to soothe the condition
• Systemic steroids, if necessary
• Propranolol class medications
• Sodium bicarbonate baths
• Antihistamine therapy seems to be effective in some cases
• Ultraviolet light therapy (UVA with oral psoralen and UVB therapy)
• Immunosuppression therapy for severe symptoms: Use of immune modulators or medications that modulate immunity
• Patient education in understanding the condition is beneficial

How can Aquagenic Urticaria be Prevented?

• Although Aquagenic Urticaria may not be prevented, further and future flare-ups may be avoided, if the triggers that cause the condition are known and recognized
• Use of suitable oil-based creams and ointments, which act as a barrier to contact of water directly with skin, may prevent further episodes of the condition

What is the Prognosis of Aquagenic Urticaria? (Outcomes/Resolutions)

• The prognosis of Aquagenic Urticaria is generally good following removal of the triggering substance (water). In most cases, the skin condition resolves on its own within an hour (the weals disappear)
• In some cases, treatment may be necessary, and the prognosis is typically good with adequate treatment

Additional and Relevant Useful Information for Aquagenic Urticaria:

Please visit our Skin Care Health Center for more physician-approved health information:

https://www.dovemed.com/healthy-living/skin-disorders/