Aquagenic urticaria is an immunopathological skin reaction induced by contact with water of any temperature. Accompanied by the appearance of blisters surrounded by an erythematous corolla, skin itching, sometimes bronchospasm or shortness of breath. The diagnosis is confirmed by a positive test during a water sample, the results of laboratory tests (determination of the level of histamine, serum immunoglobulin E, C1 inhibitor), skin biopsy. Treatment includes applying barrier agents to the skin before interacting with water, taking antihistamines, anabolic steroids, and phototherapy.
ICD 10
L50.8 Other urticaria
General information
Aquagenic urticaria is a rare form of urticaria dermatosis caused by physical factors. This type of urticaria was first described by American dermatologists W. Shelley and H. Rawnsley in 1964 To date, less than 100 cases of aquagenic urticaria (AU) are known. According to the literature, a higher prevalence is observed among women. More often, dermatosis manifests in the pubertal or post-pubertal period, but there are separate reports of the development of “allergy to water” in childhood.
Reasons of aquagenic urticaria
Clinical manifestations of aquagenic urticaria develop after skin contact with water (fresh, sea, rain, tap, distilled), sweat, saliva or tears. Skin rash occurs after washing hands, washing, taking a shower or bath, swimming in a pool or open pond, wearing wet clothes, sweating. The appearance of symptoms may depend on the salinity and amount of water, the duration of its contact with the skin.
Most cases of water urticaria are sporadic. There are several reports of familial forms of pathology, in particular, in combination with Bernard-Soulier hemorrhagic platelet dystrophy, which suggests the presence of a certain genetic locus associated with aquagenic urticaria. However, to date, no specific gene or locus has been identified. Individual cases of urticaria in the described observations were comorbid with HIV infection, papillary thyroid cancer.
Pathogenesis
The pathophysiology of aquagenic urticaria has been poorly studied. During the entire period of studying the disease, several hypotheses have been put forward, but none of them is still proven and generally accepted. So, dermatologists Shelley and Rawnsley initially suggested that when water interacts with sebum, substances are formed that in predisposed people stimulate the degranulation of mast cells with the release of histamine. Other scientists consider the presence of a certain water-soluble antigen in the epidermis to be the key mechanism, which diffuses into the dermis in an aqueous medium, causing a histamine reaction.
However, it was later proved that not all patients with aquagenic urticaria have an increase in histamine levels during the attack. This determined the search for histamine-independent mechanisms of urticaria. One of these hypotheses suggests that the appearance of a rash is provoked by a change in osmotic pressure around the hair follicles when in contact with water. Indirect confirmation of this theory are cases of the development of local aquagenic urticaria shortly after epilation.
Another hypothesis connects the appearance of blisters with other mediators: acetylcholine, serotonin, bradykinin. At the same time, it was noted that in some cases the severity of dermatosis correlates with the concentration of salt in the solution, which allows us to talk about salt-dependent aquagenic urticaria.
Symptoms of aquagenic urticaria
Clinical symptoms unfold 20-30 minutes after contact with water of any temperature on the skin. In places of contact, small blisters with a diameter of 1-3 mm appear surrounded by a corolla of hyperemia up to 3 cm. Burning, itching, tingling of the skin may be present. In some cases, skin dermographism is observed. Urticaria rashes with aquagenic urticaria more often capture the neck, upper half of the trunk, forearms, and other parts of the body. Soles and palms are usually free of itchy rash.
Skin phenomena subside within 30-60 minutes after the cessation of contact with water. As a rule, during the next few hours, the affected areas remain immune to repeated exposure to water. The extracutaneous symptoms of aquagenic urticaria include headache, dizziness, bronchospasm, shortness of breath, tachycardia, nausea.
Aquagenic itch
Aquagenic itching is quite widespread in the population – 45% of the population report its presence. Just like urticaria, it is provoked by the ingress of water on the skin, but unlike AU, it is not accompanied by visible changes in the skin. It is characterized by a tingling, tingling, burning sensation. Usually, the lower extremities are involved in the pathological process first, then other parts of the body. Itchy sensations can persist for up to 2 hours.
Aquagenic itching may be associated with old age, true polycythemia, hypereosinophilic syndrome, juvenile xanthogranuloma, myelodysplastic syndrome.
Complications
With the development of systemic reactions, aquagenic urticaria can be potentially fatal. The most dangerous complication is angioedema of the larynx, leading to asphyxia and death. The chronic course of the disease, problems with daily hygiene procedures, constant restrictions in interaction with water contribute to insomnia and neurotic disorders.
Diagnostics of aquagenic urticaria
The diagnosis of aquagenic urticaria is mainly based on anamnesis (recurrent rashes after contact with water) and provocative tests. Patients should consult a dermatologist, allergist, immunologist.
- Provocative tests. The aquagen test consists in applying a compress moistened with water at body temperature (37C) to the skin for 20 minutes. The test is positive when itchy blisters appear. Other diagnostic tests (dermographism test, ice cube test, hot water test) give a negative result.
- Laboratory tests. The level of histamine in the blood may be elevated or correspond to the norm. Sometimes, for differential diagnosis, laboratory evaluation of serum IdE, eosinophilic cationic protein, and C1-esterase inhibitor activity is required.
- Skin biopsy. Histopathological examination of the skin biopsy reveals pronounced interstitial edema, perivascular and interstitial inflammatory infiltration (lymphocytes, mast cells, neutrophils), endothelial edema.
Differential diagnosis
To make a correct diagnosis, it is important to exclude other forms of urticaria induced by physical factors:
- dermographic – caused by mechanical irritation of the skin;
- cholinergic – develops in response to the action of elevated temperature;
- cold – caused by exposure to cold;
- solar – characterized by the appearance of a rash after exposure to the sun;
- vibration – elements of urticaria rash appear in places of vibration exposure.
- aquagenic itching is characterized by the absence of visible skin changes.
It is also necessary to differentiate other skin diseases manifested by urticarian rashes: allergic dermatitis, herpetiform dermatitis, urticarian vasculitis, erythema multiforme, etc.
Treatment of aquagenic urticaria
Due to the rare occurrence of the disease, there is little data on the effectiveness of certain treatment methods. Unlike other types of physical urticaria, when it is possible to avoid contact with an etiological agent, it is almost impossible to exclude contact with water. In practical dermatology, the following methods and their combinations are used for the treatment of aquagenic urticaria:
- Antihistamines. They are first-line drugs for all forms of urticaria. Preference is given to histamine H1 receptor blockers. The appointment of H2-histamine blockers is usually resorted to when the drugs of the first group are ineffective.
- Other medicines. The monoclonal antibody Omalizumab reduces the level of free IgE, inflammatory mediators and allergies. This drug has been successfully tested on several patients with aquagenic urticaria. In some cases, the effect was noted from taking SSRIs, anabolic steroids, m-cholinolytics.
- Local funds. It is recommended to use vaseline-based creams and cosmetic oils as barrier agents before contact with water and bathing. This therapy option is suitable primarily for pediatric patients.
- PUVA therapy. Some reports indicated that it was possible to eliminate symptoms after sessions of systemic PUVA therapy and PUVA baths. Ultraviolet irradiation of the skin is carried out after taking psoralen. The effectiveness of phototherapy is associated with both a decrease in the reaction of mast cells and a reactive thickening of the epidermis, which prevents the penetration of water.
Prognosis and prevention
When conducting individually selected treatment, in many cases there is a clinical improvement. Cases of spontaneous regression of the disease are unknown. Many patients suffering from aquagenic urticaria are immune to any treatment. The only way out for them is a lifelong restriction of interaction with water, minimizing bathing time, avoiding certain types of activities. Due to the fact that the pathogenetic mechanisms remain unclear, it is not possible to talk about preventive measures.
