Lee S, et al. – In this study, researchers summarized the clinical outcomes of contact immunotherapy for alopecia areata according to standardized criteria for therapeutic hair regrowth and several prognostic factors. Findings suggested the association of various factors with the clinical outcomes of contact immunotherapy for alopecia areata, with significant differences in hair regrowth rates according to the level of expected therapeutic regrowth. Patient education may be improved by quantitative summarization, which may lead to better therapeutic adherence and outcomes.

Methods

• Experts performed a database search of MEDLINE, Embase, and Cochrane Library for articles published before November 20, 2017, using the search terms areata, totalis, universalis, sensitizer, sensitization, immunotherapy, DPCP, diphenylcyclopropenone, diphencyprone, SADBE, and squaric.
• They included the clinical trials or observational studies that investigated contact immunotherapy for alopecia areata, sub-grouped the disease into patchy alopecia or alopecia totalis/universalis, and reported their hair regrowth rates; the excluded studies that investigated combination therapy, nonconventional protocol, case series, or reviews.
• They extracted the following data from each of the studies included in this meta-analysis: study year and setting, sensitizer type, study population, study population composition by disease subtype, defined criteria for therapeutic hair regrowth, and regrowth rate of contact immunotherapy.
• Furthermore, they recorded the incidence of adverse effects and recurrence rate.
• For data synthesis, a random effects model was used because of the expected high heterogeneity of the included studies.
• Therapeutic hair regrowth rate according to the four-grade criteria for therapeutic regrowth was the main outcome.
• Incidence of treatment-related adverse effects and recurrence rate were included in the secondary outcomes.

Results

• Researchers evaluated 45 studies representing 2,227 patients.
• Among patients with alopecia areata, the overall rate of any hair regrowth was 65.5% (74.6% in the patchy alopecia and 54.5% in the alopecia totalis/universalis subgroups).
• Nonetheless, 32.3% was the complete regrowth rate (24.9% in the patchy alopecia and 32.3% in the alopecia totalis/universalis subgroups).
• Findings suggested an association of disease extent of ≥ 50% (odds ratio [OR], 3.05; 95% CI, 2.26-4.12), atopic history (OR, 1.61; 95% CI, 1.03-2.50), and nail involvement (OR, 2.06; 95% CI, 1.26-3.36) with poorer therapeutic outcome.
• Among patients receiving maintenance treatment, recurrence rates were 38.3% and it was 49.0% among those not receiving maintenance treatment.