Diphenylcyclopropenone (DCP) Treatment for Alopecia Areata

For over twenty years doctors have been using topical contact sensitizers to treat alopecia areata. Diphenylcyclopropenone (DCP) is the most common contact sensitizer that is currently in use. While it is not a mutagenic according to the James' test, it is extremely photo-labile. It has photo-mutagenic properties as well. DCP is degraded with ultraviolet light easily. Therefore, DCP is generally mixed with ethanol, cylcohexane or acetone then kept in darker glass bottles at room temperature.

Effects of treatment through DCP

The first test of DCP with humans began in 1983 when twenty-seven patients, ranging in age from fifteen to fifty-five, where chosen for a clinical trial. Of the patients, twenty-two had alopecia totalis, while the other five had twenty-five percent hair loss on their scalps. The concentration of DCP was at two percent. The patients had half of their heads treated and the other half untreated for weekly treatments. There dosages were adjusted depending on how the patient responded to the DCP treatment and the patients received the treatments for four to seven months. Of the twenty-seven, twenty-three observed hair growth.

Many studies of the same sort were done later that also showed that DCP was useful in the treatment of alopecia areata. Responses to these studies have varied. In one clinical trial, 56 patients were treated for six to twelve months on half of their scalp. If they had hair growth, the other half was treated, which was 52 of them. Six months later 48% of them or 25, had complete hair growth and 60% had a good response.

Application of treatment

DCP treatments is a process with two steps. First, the patient gets sensitized with a DCP solution of 2%. This causes the skin to be inflamed, with redness, swelling, blisters and/or itchiness. These are all signs that the sensitizer is working. How bad the inflammation is will depend on the person and their sensitivity to DCP. The first step usually takes two weeks.

Second, the patients are given treatments on a weekly basis with increasing concentrations of solution. The concentration can vary from 0.01% to 1%. The goal is to get the concentration to a level that will cause the skin to have an allergic reaction that results in an eczema or dermatitis condition but with no blisters or oozing. The concentration level will vary during the treatment period. The residue of the DCP will be washed off two days after the weekly treatment. Some studies have the patients do the treatment while others have nurses apply the DCP solution.

Results of treatment

Hair will begin to regrow noticeably about 8-10 weeks after the treatments start. After this the treatments will continue on a weekly basis. Then the treatments frequency will be lowered and continued until satisfactory hair growth has been achieved, at which time the treatment is stopped. If there is a relapse, treatment can be immediately resumed to keep the hair loss to a minimum and regrow any lost hair.

There are many factors that will influence the effectiveness of DCP treatments. In one study 139 patients who had extensive alopecia areata were treated. Three main factors were identified that had a negative impact on results: the amount of pre-treatment scalp involvement, how long the patient had suffered from alopecia areata, and if the patients had nail aberrations. Some factors that had no effect on results were: age, gender or atopic features.

Side effects

One of the most common side effects of DCP is pruritus. Pruritus is a severe itch or feeling that makes the patient want to scratch their scalp. Not only can it cause discomfort but a great deal of stress and frustration as well. Severe cases of pruritus will cause patients to be anxious, sleepless and lead to depression. What causes the itch is not yet known. DCP treatments are complex and effect the nerves that are responsible for responding to chemicals such as histamine that the skin releases. It also effects the process in which these nerves communicate through signals to the brain.

Dermatitis that is mild or severe can occur. Dermatitis is simply a broad term that means that the skin is inflamed in some way. While it is also a common side effect, it is certainly not life threatening but can make life miserable for the patients. In severe, untreated cases, it can cause skin infections. Usually it is easily maintained with better skin care plus the administration of medications both orally and topically.

A more severe side effect is regional lymphadenopathy. Lymphadenopathy is a condition that is marked by swelling or enlarging lymph nodes. There are many reasons why the treatments may cause the lymph nodes to become swollen. There can also be fever, tenderness and/or redness at the various lymph node locations.

One of the less common of the possible side effects is urticaria, better known as hives. These hives are usually in or near the treatment area. They are itchy, pink and pale swollen areas that can be accompanied by a stinging or burning sensation. There can be just one or groups of hives on any area of the skin but they are usually on the skin that comes in contact with DCP. The hives formulate when blood plasma leaks through the small gaps that are between cells that line the small blood vessels in the skin.

Also a side effect that does not occur often is vitilgo. Vitilgo is when the skin loses pigment color. Some patients experience spots that are much lighter than their normal skin tone and can actually turn completely white. Then there are others that have wider losses of color. While the condition can appear on any area of the body it is mostly on the hands, feet, face and forearms. Once it appears there is no way to tell how much color will be lost and there is no way to reverse it.

Conclusion

The DCP treatment has not yet been approved by the FDA as a drug for the treatment of alopecia areata. So far the clinical trials have had a median success rate of 43%, making it a fairly effective treatment. Success is not measured in the regaining of all hair, just a significant regrowth of hair. Since the treatment is experimental, the effects over the long term are not completely known.