Iontophoresis

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Iontophoresis

Definition

Iontophoresis is a procedure that uses a small electric current to increase the permeability of the skin.

Purpose

Iontophoresis is used for several distinctly different purposes. These include:

to perform a "sweat test" to diagnose cystic fibrosis.
to treat excessive sweating of the hands and feet (hyperhidrosis) that does not respond to prescription antiperspirant treatment
in physical therapy to deliver drugs locally to musculoskeletal disorders such as tennis elbow
to deliver drugs to treat localized skin diseases such as eczema and psoriasis.

Precautions

Pregnant women, people with large metal implants, and people with implanted pacemakers should not have iontophoresis. In other people, the electric current used on the skin is very low and is not harmful. However, there have been cases where burns and electric shocks have been caused by equipment malfunctions. Allergic reactions can also occur to drugs used during iontophoresis procedures.

Description

Iontophoresis is generally performed in an outpatient or physical therapy setting. The skin is cleaned, and medication is applied, then electrodes are placed over the site. In the sweat test for cystic fibrosis, the drug pilocarpine is applied to stimulate sweating. The electrodes deliver and low voltage electric current for about 10 minutes to stimulate sweating. The electrodes are then removed. The skin is washed with distilled water, and a piece of filter paper is placed on the site to absorb the sweat. The filter paper is sealed with paraffin wax. After an hour the paper is removed and analyzed for chloride content. People with cystic fibrosis characteristically produce more salt (sodium chloride) in their sweat than people without the disease.

When iontophoresis is used to treat skin and musculoskeletal conditions, different drugs are placed under the electrodes, and the time of stimulation varies depending on the disorder being treated.

When iontophoresis is used to treat hyperhidrosis, the feet or hands are submerged in water for 20 to 40 minutes and an low electric is sent through the water. Sometimes anticholinergic drugs are added to the water. The reason this treatment is successful has not been fully explained.

Preparation

No special preparation is needed before iontophoresis.

Aftercare

After removing the electrodes and washing the skin, no special aftercare is needed, No disability or delayed recovery is expected from this treatment.

Complications

No complications are expected with this procedure.

Results

The effectiveness of iontophoresis has been questioned when used to drive drugs across the skin to treat musculoskeletal disorders such as tendon strains or to treat skin conditions. Although anecdotal evidence suggests the effectiveness of iontophoresis in physical therapy and dermatology, several controlled studies have failed to show that iontophoresis produces a greater improvement over more traditional treatments. For this reason, some insurers consider the use of iontophoresis as a drug delivery system in physical therapy and to treat skin conditions to be investigational and do not cover the cost of this procedure.

Use of iontophoresis in diagnosing cystic fibrosis and to treat excessive sweating is considered accepted practice and is normally covered by insurance. Individuals treated for excessive sweating will need regular repeat sessions of iontophoresis at intervals ranging from once a week to once every four weeks or whenever sweating reoccur. With regular treatment, the American Academy of Dermatology reports that hyperhidrosis is controlled in about 80% of people. Iontophoresis cannot be used to treat excessive underarm sweating.

Health care team roles

Iontophoresis is often administered by a physical therapist, however drugs used with the procedure must be prescribed by a physician. When used to test cystic fibrosis, iontophoresis is usually administered by a laboratory technician or nurse. A dermatologist oversees the use of iontophoresis when treating hyperhidrosis.

KEY TERMS

Anticholinergic drug— A drug that interferes with the transmission of parasympathetic nerve impulses and reduces the contraction of smooth muscle.

Eczema— A non-contagious skin disorder that causes redness, itching and crusty or scaly sores.

Hyperhidrosis— Intense, excessive sweating on the soles of the feet, palms of the hands, or underarm area.

Permeability— The degree to which materials such as drugs or ions pass through a barrier such as skin or cell membranes.

Psoriasis— A chronic inflammatory skin disease possibly related to an immune system disorder.