Topical immunotherapy with diphencyprone in Indians with alopecia areata

S ir, Treatment of alopecia areata has included topical or systemic corticosteroids, cyclosporin, photochemotherapy, minoxidil and topical immunotherapies.1 Dinitrochlorobenzene (DNCB) is mutagenic and squaric acid dibutyl ester is unstable, whereas diphencyprone (2‐3‐diphenyl, cyclopropenone‐1) (DPC) is devoid of such effects2 and many studies from different parts of the world have reported the efficiency of this agent.1–3 Response is known to vary with different populations and there are no reports from India. Fifteen patients with alopecia areata with a mean age of 19.5 years (range 5–34 years) and mean duration of alopecia of 5 years (range 1 month to 25 years) were recruited for the study. Six had alopecia universalis and three each had alopecia totalis, extensive alopecia areata and circumscribed alopecia areata. One patient had alopecia areata confined to the beard and another to the extremities and trunk. Four patients had associated atopy and seven had nail changes. All patients had received topical steroids and three patients had failed to respond to systemic steroids at 300–1000 mg in pulsed doses. Sensitisation with DPC was performed as previously described.4 This was with 2% DPC in acetone applied to a 2.5 cm2 area of the left half of the scalp; rechallenge was carried out 10 days later with 0.1% DPC on the right half of the scalp. In two patients, sensitisation with 1% DPC was performed on a patch of alopecia areata on a limb or on the beard area. Subsequently, DPC was applied weekly at concentrations ranging from 0.001% to 0.1% as required to produce and maintain minimal dermatitis. Response was assessed at monthly intervals by serial photographs and results were tabulated at 6 and 12 months. Treatment was considered successful only if there was sufficient hair regrowth for the patient to discard the cap or wig. In patients with complete hair growth, 2–3 weekly application of DPC was continued for up to 2 years. Complete blood count, hepatic and renal function tests and urine analysis were carried out before DPC and at 3 month intervals during treatment. Of 15 patients recruited, one dropped out at 2 months and another has been recruited recently. Eleven (84%) of 13 patients achieved sensitisation with DPC. Three developed tolerance to the preparation during treatment and could not be resensitised even with a 5% solution. Three (33%) of 10 patients showed complete or near complete hair regrowth (Fig. 1a,b). They included two patients with, respectively, universal and total alopecia for more than 5 years. Response was evident at 6 weeks and cosmetically acceptable at 5–6 months. Two patients, however, developed small patches of alopecia during the maintenance phase of up to 2 years. Another patient of circumscribed alopecia areata in the beard area showed more than 75% regrowth at 6 months and is still under follow‐up. The patient with extensive alopecia areata confined to the extremities and trunk showed no hair regrowth despite extreme sensitivity to DPC. (a) Lateral view of a patient with alopecia totalis before treatment; (b) the same patient after treatment with topical DPC. Vitiligo‐like depigmentation and hypopigmentation at the treated sites were each observed in one patient, and an irritant reaction was recorded in three. None had abnormalities in laboratory parameters. The success rate of DPC sensitization has varied between 17% and 85%;3 the efficacy rate of the present study (33%) is on the lower side of this range. Severe disease, alopecia of longer duration, nail involvement and atopy is associated with a poor response.3, 5, 6 Most of our patients had poor prognostic factors and this might have been the reason for the poor response. Response to DPC at sites other than the scalp was poor and similar observations were made when patients were treated with oral prednisolone pulse.7 The number of side effects of DPC observed in the present study is similar to that reported previously and should be considered when choosing topical immunotherapy; particularly since the level of depigmentation was high even in the patient with complete hair regrowth. We conclude that DPC has a low and unpredictable efficacy in the treatment of alopecia areata.