Retrospective review of diphencyprone in the treatment of alopecia areata.

Background: Contact immunotherapy with diphencyprone (DCP) is used to treat alopecia areata (AA). Its reported efficacy is variable, and individual response cannot be predicted.

Aim: To identify patient and treatment course variables that may affect treatment outcome, and to review DCP service to identify potential areas for development and improvement.

Methods: This was a retrospective review of a DCP service over a 20-year period (1991-2010).

Results: Complete data was available for 205 treatment courses, and 162 (79%) treatment courses were completed for 133 patients. Overall, 72.2% (96/133) of patients had some hair regrowth (any grade). In 15.8% of cases (21/133), response was > 90% regrowth. However, 27.1% (36/133) had no response. We found that extent of alopecia at baseline and duration of disease were statistically significant when comparing patients with an optimal outcome to those without (P < 0.05). In contrast to other reports, atopy, age at onset and nail dystrophy were not statistically significant. For patients receiving more than one course, response to DCP treatment was broadly consistent.

Conclusions: Extent of alopecia at baseline and duration of disease are important factors in predicting response. Our results suggest that atopy should not be considered a predictor of poor outcome with respect to DCP treatment. A need for improved data collection, particularly regarding longer-term outcomes, was identified. The role of maintenance therapy requires objective assessment. Opportunities for DCP self-administration by patients should be explored. Limitations of this study include the retrospective nature of the review and lack of long-term follow-up data.