Aquagenic itching: when water is the enemy

Only a person who has never had to deal with some form of persistent or recurrent itching can think that it is a trivial disorder. Those who have experienced it at least once, know well that the discomfort it can cause on a physical and psychological level is very considerable, both when it is intense and localized in a circumscribed area of the body, such as the hands, arms, feet or head, and when it is more modest, but extended over a large skin surface, such as the abdomen, the legs or the back.

In addition to creating significant discomfort, the continuous urge to scratch is a source of considerable stress, which prevents you from relaxing and concentrating on the activities you are doing, making you nervous, irritable, in a bad mood. In addition, when it occurs or intensifies in the evening or at night, it can hinder falling asleep or cause repeated awakenings, adding to the basic discomfort also the unfavorable effects of insufficient rest, namely physical and mental fatigue, reduced intellectual performance, further nervousness and general malaise.

Regardless of its origin, the reduction in quality of life that derives from the presence of itching for prolonged periods is completely comparable to that determined by chronic pain, with the aggravating circumstance that remedies to relieve itching do not always manage to be as effective as analgesic ones. In addition, often, there is less understanding and empathy towards those who suffer from this discomfort, especially when the cause is not clear or is considered “extravagant”, to the point of wondering if it is a real sensation or only imagined, as in the case of aquagenic itching. Let’s see what it is.

Aquagenic itching: what is it

Aquagenic pruritus is a very rare form of itching induced by simple skin contact with water. It typically occurs after bathing or showering and can affect various parts of the body, regardless of the cleansing products used and the washing methods, as a result of a sort of intolerance to water by the skin.

Any type of water can trigger aquagenic itching: drinking water that comes out of the tap, regardless of the degree of hardness (corresponding to the amount of calcium and magnesium salts dissolved), to rainwater; from distilled to pool water with added chlorine. Even sweat, physiologically produced by the same person during physical activity or when in hot environments, can induce the skin reaction that leads to the onset of the itchy sensation.

And the temperature of the water or the timing of the contact make no difference either: whether it is hot or cold, whether the bath or shower lasts a few minutes or is prolonged longer, if you are predisposed to develop aquagenic itching, the discomfort will not fail to occur, making the experience of washing or a swim very unpleasant and, as far as possible, preferably to be avoided.

Conversely, it has been observed that hypertonic solutions, containing a quantity of salts higher than that present in the fluids and cells of the body (such as sea water and solutions of water and bicarbonate), cause less problems of aquagenic pruritus.

To suffer from this singular disorder are mainly women, in whom it begins from a young age, often around 18 years, or during pregnancy.

When itching after contact with water begins to occur between the ages of 50 and 70, it could be polycythemia vera: it is a rare blood disorder characterized by an increase in red blood cells (and sometimes also white blood cells and platelets), which must be treated specifically to reduce the risk of acute vascular events (arterial and venous thrombosis), pulmonary embolism, hemorrhages, angina and intermittent claudication.

Causes of aquagenic itching

The causes of aquagenic itching are not well understood. Although it is often considered a sort of “water allergy“, in reality when it occurs there is no typical allergic reaction with the production of specific immunoglobulins E (IgE): a fact, moreover, quite predictable since common water does not contain substances capable of stimulating the immune system to produce antibodies.

The sensation of itching, accompanied by tingling and burning, seems to be determined by the action of the so-called “vasoactive peptides”, such as acetylcholine, ie small protein fragments produced by cells of the immune system called mast cells.

Once released into the tissues, vasoactive peptides regulate skin sensitivity, acting on the nerve structures present in the dermis, resulting in modulation of the threshold of itching, burning and pain. In essence, their excessive release by mast cells would make the peripheral nerve endings more sensitive and reactive, causing “exaggerated” or distorted perceptions in the face of minimal stimuli (a condition known as allodynia).

It remains to be understood why in a given person this mechanism is activated only during the contact of the skin with water (or sweat) and not with other solutions richer in salts or with substances known to induce allergy, for example latex, animal hair, sensitizing metals such as nickel etc.

Symptoms of aquagenic itching

Aquagenic itching is a skin sensation that resembles a shower of pinpricks on the skin, sometimes preceded, accompanied or followed by tingling and other types of paresthesias (changes in sensitivity).

All parts of the body can be affected, even in a variable way depending on the day, but generally the discomfort is localized mainly at the level of the limbs (arms and legs, in particular between ankles and calves), while it is rare that it affects the palms of the hands, the soles of the feet or the face (unlike what happens for other forms of itching associated with the presence of an allergy).

If it is “pure” aquagenic itching, as a rule, there are no other manifestations and the skin appears completely intact and free of signs of any kind, except those associated with any scratching lesions, which can transform the itching into intense burning and pain, damage the skin surface, induce erythema, dry or thickened skin, as well as promoting the risk of infections.

Conversely, if together with the itchy sensation there are also bumps, more or less reddened and embossed, or reddish-purple lumpy and confluent spots (similar to a herpes) you can be faced with an “aquagenic urticaria“, corresponding to a more complex form of water intolerance, also characterized by intense itching.

Aquagenic itching and aquagenic urticaria tend to cause greater discomfort after summer, while tanning disappears, and in the autumn months and are promoted by contact with synthetic fiber clothing, especially if adherent and not very breathable.

If you experience an itching of this type or other paresthesias, even if not particularly serious, after simple contact with water or spontaneously, it is always good to consult your doctor for a verification of the situation and proceed to any further investigations, with the support of a specialist in dermatology or a neurologist.

In addition to confirming the possible diagnosis of aquagenic pruritus and defining its characteristics, medical consultation is essential to exclude the presence of other diseases affecting the immune system or nervous system, as well as complications of diabetes affecting peripheral nerve endings (diabetic neuropathy) or other neurodegenerative conditions.

Remedies for aquagenic itching

Against aquagenic itching, at the moment, there is no effective cure in all patients. However, there are some remedies and practical measures that can alleviate skin discomfort, to a variable extent from case to case.

Unfortunately, since an allergic reaction based mainly on histamine is not involved, antihistamine drugs can offer limited relief. Better answers were obtained with the application of creams containing capsaicin: a natural active ingredient contained in chili peppers, also used to relieve residual neuropathic pain after a reactivation of Herpes Zoster (shingles).

Exposure to UVB rays (natural or with sunlamps) can also alleviate the symptoms of aquagenic itching. To prevent its onset, however, you can try to wash by adding baking soda to the water to make it slightly hypertonic, like sea water.

A key aspect to consider to reduce the reactivity of the skin in all forms of itching, associated or not with urticaria or dermatitis, is the protection of the skin barrier, the first defense of the skin against any physical and chemical stress coming from the external environment.

An intact and efficient skin barrier prevents dehydration and the appearance of dry skin (which in itself favors the onset of itching), reduces the penetration of allergens and irritants / sensitizers into the deep layers of the dermis (where they can stimulate the local immune system) and helps prevent the inflammatory skin reaction.

To protect it, it is necessary to reduce the number of washes (balancing daily hygiene needs with an acceptable degree of skin stress) and regularly apply high quality emollient and moisturizing creams, after each bath or shower to protect and give relief to the skin.

Ideally, creams containing lipid substances similar to those naturally present in the skin (ceramides), humectant agents capable of recalling and retaining physiological water inside the epidermis (glycerol) and substances capable of promoting the regeneration of the skin barrier (such as panthenol) should be used.

Starch glycerolate preparations also seem to help prevent/control aquagenic itching.

Other tips and practical measures that can help improve the well-being of skin predisposed to aquagenic itching or other forms of sensitization include:

• limit sweating as much as possible, dressing in layers, using air conditioning systems in summer and avoiding exceeding with heating in winter
• wear soft and comfortable clothing, made of natural fibers that are well breathable and able to quickly absorb moisture deriving from skin perspiration (especially if you have a dynamic life and when practicing physical activity)
• avoid any form of rubbing of the skin, both that of scratching, and that during washing and drying
• wash only with your hands and dry by dabbing with very soft sponges
• use very delicate detergents of excellent quality or a washing oil, so as not to excessively destabilize the skin barrier
• follow a balanced diet and a lifestyle favorable for the health of the whole organism
• limit the intake of vegetables of the Solanaceae family (potatoes, eggplants, tomatoes, peppers, Goji berries, etc.), which seem to increase the symptoms
• avoid excessive psychophysical stress and get enough sleep, following regular sleep-wake rhythms
• Avoid smoking and reduce caffeine and alcohol consumption.

For the most severe forms of aquagenic itching or due to aquagenic urticaria, which do not draw relief from the indicated remedies and which involve a serious deterioration in quality of life, topical or systemic corticosteroids and antidepressant drugs can be used on prescription; Recently, the use of biological drugs (monoclonal antibodies) has also been proposed.