This is the introduction of an ionized substance through intact skin by application of a direct current. It was first use by Ichihashi in 1936 when he used this technique to try and decrease palmar sweating with application of atropine, histamine, and formaldehyde. It was not until 1952 with the report of Bouman and Gruenwald Lentzer that this became more widely noticed. They also demonstrated that a chemical substance did not need to be added to the water for therapeutic effect.
Iontophoresis of hands using a Fisher Galvanic unit
|1. Fill the 2 plastic trays with tap water at room temperature to the top of the electrodes.|
|2. With the Fischer unit off, connect the trays to the unit’s outputs with the supplied cords.|
|3. Remove all jewelry and cover any small cuts or abrasions with Vaseline or equivalent.|
|4. With the unit still off, the subject places 1 hand in each tray. The water level should be just above the skin.|
|5. Turn unit on with meter scale set from 0 to 50 and “intensity” knob at zero and gradually increase the current to 15 to 18 mA, and treat for 10 min.|
|6. At the end of the 10 min, decrease the current flow gradually to zero, then when the active light goes out, change the direction of current flow using the “Nor-Rev” toggle switch.|
|7. Repeat steps (5) and (6) for 10 min.|
*If the red light does not illuminate when attempting to increase the current flow, return to the switch to zero and check all connections.
The mechanism of iontophoresis is thought to be due to plugging of the pores as if cellophane tape is applied to the skin overlying the sweat glands and then pulled off (tape stripping), the effect is immediately reversed.
Tap water iontophoresis is a first-line therapy for palmar and plantar hyperhidrosis because of its low side effect rate. A small electric current is passed through a small bath into which the hands and feet are soaked for a few minutes a week. This seems to decrease the sweat production from the glands. Direct current applied continuously is preferred as pulsed direct current is slightly less effective. It is thought that the iontophoresis results in a disruption of the normal ion transport in sweat glands, perhaps because of accumulation of the positively charged protons (H+) in the sweat gland ducts. 80% of patients find this useful in terms of symptom suppression, but it requires considerable investment in time with at least three sessions per week being needed initially and then one per week for maintenance therapy. Side effects include erythema, local burning, pain and blistering. Occasionally, the palms may become cracked and fissured if they are too dry, thus requiring decreased frequency of treatments and barrier creams.
Specialist equipment such as the Fischer MD-1a Galvanic unit is required with 5 to 10 treatments claimed to lead to upto an 85% benefit, although a 50% reduction is a more typical figure. This is similar to the reduction seen with 20% aluminum chloride hexahydrate in 95% ethyl alcohol has a similar success rate. Iontophoresis together with 0.05% glycopyrrolate is significantly more effective than tap water
Iontophoresis is difficult to administer to the axillae, causes more irritation, and is generally not useful.