Diphenylcyclopropenone, sometimes called, diphencyprone can be used to treat extensive alopecia areata

Alopecia areata hair loss information for men and women
Alopecia Areata 
Alopecia Areata Biology
Alopecia Areata Treatments

  Diphenylcyclopropenone (DCP) Treatment of Alopecia Areata
 

Topical contact sensitizers have been in use for treating alopecia for around twenty years. Diphenylcyclopropenone or DCP is currently the most commonly used contact sensitizer. Although it is non-mutagenic in the James’ test, it is very photolabile. It also possesses potential photomutagenic property. DCP is also very easily degraded by ultraviolet light and is therefore usually mixed with acetone, ethanol or cyclohexane and stored in dark glass bottles kept at room temperature.

Treatment by CP is normally a two-step process and starts with the sensitization of the patient with a 2% DCP solution. The skin becomes inflamed, exhibiting redness, swelling, itchiness or blisters, indicating that the contact sensitizer is working. The severity of the inflammation varies with individuals and depends on their sensitiveness to the DCP solution. This sensitization process normally takes two weeks to complete.

The second step of the process involves weekly applications of the solution with increasing concentrations. This concentration varies from 1% to 0.01% or from 0.001% to 0.0001%. The aim of this process is to get the correct concentration, sufficient to draw out a mild allergic response of contact dermatitis or eczema but, importantly, one without any blistering or oozing. This target concentration sometimes varies during treatment Two days after the end of these weekly applications, any residual DCP can be washed away. In some studies the weekly applications were made by the patients themselves and in others by the nurses.

Hair growth is first observed normally eight to ten weeks after commencement of treatment. Weekly applications are continued to trigger proper hair growth. Later the frequency of the applications is reduced to a maintenance dose until complete hair regrowth is obtained. Eventually the treatment is discontinued. However, in case of a relapse, treatment is immediately restarted to prevent the progress of alopecia areata and induce hair growth.

Studies on the stability of DCP in acetone have shown that by the third month there is significant evaporation of acetone, so that the effective shelf life of DCP in acetone is no more than three months. Also, evaporation of acetone increases the concentration of DCP, which is why, as mentioned earlier; the target concentration sometimes varies during treatment.

Since DCP is unstable it is recommended that its preparations be kept refrigerated in amber bottles at 4 degrees centigrade. In the U.S. the FDA is currently concerned about the sources of DCP and is working out safety norms for this drug. The drug is still to get FDA approval.

It was in 1983 that the first clinical trials of DCP in alopecia areata were conducted. 27 patients aged 15 to 55 years were selected for the trial. Of these 5 had more than 25% scalp hair loss and the remaining 22 had alopecia totalis. Sensitization was obtained at 2% concentration and one half of the scalp was treated, the other half left untreated to serve as a control. During the course of the weekly treatments, adjustments were made in the dosage depending on the response of the patient to the DCP. The duration of the treatment varied from four to seventeen months. Hair growth was observed in 23 out of 27 patients.

A number of such studies conducted later also reported success of DCP in alopecia areata treatment. Responses have of course varied. In one study, 56 patients with extensive chronic alopecia areata were treated with DCP. After sensitization, weekly applications of 0.001% to 2% DCP concentration were given. Such applications of progressively higher concentrations of DCP were given to one half of the scalp and continued for 6 to 12 months. If hair regrowth was observed on the treated half, the treatment was extended to the entire scalp. 52 subjects went through the entire trial. After six months 25 out of 52 patients i.e. 48% showed complete regrowth and 60% showed persistent response. A retrospective study of patients who were treated for at least 5 months for at least 40% scalp hair loss showed that around 71% had a response and 31% achieved a remission.

Alopecia in Children

DCP has also been used for pediatric treatment. In one study 12 children were treated with DCP. Four of the children had extensive alopecia areata and eight had alopecia totalis. Eight of these twelve patients had hair regrowth and the remaining four had complete regrowth. Six months after discontinuation of treatment three out of these four maintained their hair and one lost all the new growth.

Prognosis

To determine the factors influencing prognosis a study by Van der Steen et al was undertaken on 139 patients with extensive alopecia areata, who were treated with a topical application of DCP. Three factors were found which had a significant negative prognosis:

  • Degree of scalp involvement before treatment
  • Duration of alopecia areata before treatment
  • Presence of nail aberrations

Factors that did not have any significant effect on the response to topical therapy were:

  • Age of onset
  • Sex of patient
  • Presence of atopic features
  • Extent of variation in the range of DCP concentrations used in the therapy
  • Sleep disturbances because of pruritus.

Another study by different authors reported that DCP was unable to reverse the hair loss if alopecia areata becomes active. During periods of activity, besides loss of new hair, there was also a decrease in sensitivity to topical DCP.

Predictive Model for DCP Therapy

A recently published predictive model by Wiseman for immunotherapy with DCP reported that at 33 months, 60% of alopecia areata patients had clinically significant hair regrowth, whereas the figure was 17% in case of alopecia totalis/universalis patients. 80% of the patients showed a clinically significant growth at 32 months. They, therefore, advocated at least two years of therapy. 63% patients had a relapse after 35 months of therapy, without the influence of maintenance therapy, as was the case in the study by Van der Steen.

Side Effects

Common side effects in DCP therapy are pruritus, mild to severe dermatitis, regional lymphadenopathy and sometimes disturbed sleep due to pruritis. Less common side effects are urticaria, erythema multiforme like reactions, vitiligo, arthalgias and fever.

Conclusion

DCP is not an FDA approved therapeutic drug. Although with a median response rate of 43% it is relatively an effective therapy. It is still an experimental treatment and its long term effects are unknown.



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