Tap Water Iontophoresis: Treatment, Effects & Risks

Tap water iontophoresis is mainly used to treat hyperhidrosis and dyshidrosis on the soles of the hands and feet, as well as other defined areas of the skin, using direct current. Treatment is performed with either continuous or pulsed direct current, although pulsed direct current is more comfortable and suitable for young children, but has weaker therapeutic effects.

What is tap water iontophoresis?

Tap water iontophoresis (LWI) consists of direct current treatment of specific areas of the skin, such as the palms of the hands and soles of the feet, using appropriate devices. The most common devices consist of two small tubs, in each of which a flat electrode is placed with the size of the sole of a foot, so that the feet or hands can comfortably fit on it. The tap water in the two trays serves only as a contact medium between the electrodes and the skin. Alternatively, two sponge electrodes soaked in tap water can be used to treat other areas of the skin. Tap water iontophoresis can be performed with either continuous or pulsed direct current for the treatment of excessive sweat production (hyperhidrosis and dyshidrosis). Since pulsed iontophoresis is considered less effective, only continuous direct current is used for the treatment of severe hyperhidrosis. The efficacy of tap water iontophoresis in terms of reduction of sweat production in the treated areas has been demonstrated, but the physiological processes of the principle of action are not yet fully understood and are the subject of controversy.

Function, effect, and goals

The main areas of application are in the reduction of pathologically increased sweat production on the soles of the feet, palms of the hands, and the armpits. Hyperhidrosis occurs predominantly on the palms of the hands, the soles of the feet, and in the armpits. It is a sweat production that does not primarily serve thermoregulation. Rather, it is due to a dysfunction caused by a hormonal disorder (e.g. hyperthyroidism) or to excessive stimulation of sympathetic nerve fibers, which stimulate the affected sweat glands to pathological overproduction. Even in the case of less severe dyshidrosis, which carries with it secondary conditions such as hand and foot eczema, recurrent fungal infections or multiple warts, tap water iontophoresis can bring relief and healing. Another application of LWI is the treatment of keratoma sulcatum, which is caused by a bacterial infection. The cornea on the soles of the feet is covered with small worm-like holes. This disease is also favored and enabled by hyperhidrosis. The standard method of applying LWI is continuous (galvanic) direct current, because experience has shown that this achieves the best results. Pulsed direct current is used only if the patient is a small child or a person who is hypersensitive to continuous direct current. There is still no consensus among experts about the actual principle of action of LWI and why the procedure is highly successful. One of the hypotheses is that the weak direct current disturbs the transport of ions in the secretory tangle of the sweat glands, which prevents the glands from responding effectively to the “commands” of the sympathetic nerve fibers. According to another hypothesis, there is an accumulation of hydrogen ions in the excretory ducts of the glands, resulting in a low pH that causes damage to the excretory ducts. According to a third theory, the positive cations and negative anions dissolved in tap water influence the membrane potentials so that desensitization of the cells is achieved, as evidenced by normalization of sweat secretion. An LWI therapy usually covers a period of 5 to 6 weeks with three to five applications per week during the initial phase. A single application lasts about 10 to 15 minutes. During the later “maintenance phase”, an application once or twice a week is sufficient. The maintenance phase must be followed up because the desensitization of the sweat glands is reversible and without follow-up treatment the hyperhidrosis would reappear.The therapy is very well suited for applications at home and is then also very inexpensive, apart from the purchase of a device. The aim of the treatment is always to reduce sweat production to normal levels on the areas of skin affected by hyperhidrosis.

Risks, side effects and dangers

Tap water iontophoresis is virtually free of side effects if the equipment is handled properly. There is no age restriction, except for children under 6 years of age, for whom treatment should only take place under supervision. The plate electrodes in the small tubs are made either of nickel-free material or even of neutral silicone, so that even patients with a nickel allergy need have no fear of an allergic reaction. This also applies to people who have allergic reactions when in contact with chrome or other metals. They should only use devices with silicone electrodes. In case of improper handling and sudden immersion of hands or feet into the tray with the electrodes, a mild electric shock (willow fence effect) may occur. Otherwise, the treatment is completely painless, except for a slight tingling sensation that may be felt by sensitive patients at high operating levels of the device, or a slight twitching of individual muscle cords may occur at irregular intervals. Because no data are available for pregnant women, LWI is contraindicated for them. The same applies to persons who have been implanted with an electronic device, such as a pacemaker. There should be no metallic implants near the treated skin areas, as they could heat up.