Patch test reactions in patients with the additional diagnosis of vitiligo

Melanocytes involved in vitiligo may have inherent aberrations that make them vulnerable to extracellular insult. Allergic contact dermatitis (ACD) has been implicated in the development and progression of vitiligo. This study was conducted to investigate the association between ACD and vitiligo.

A total of 125 patients with vitiligo, who showed lesions in particular locations, onset at an older age, and/or pre-existing inflammation or pruritus, were included. Patch tests were performed using a Korean standard series. In order to investigate the association between avoidance of allergen and clinical improvement, 43 vitiligo patients who showed positive reactions to the patch test completed a questionnaire administered by telephone and self-assessed the status of their condition using a 10-point scale.

A total of 98 (78.4%) of 125 patients with vitiligo showed positive patch test reactions to at least one antigen. Although a limited number of contact allergens may have specific predilection sites, a significant association (P = 0.002, odds ratio 3.06) was found between lesions distributed on the scalp and/or hairline and a positive patch test reaction to paraphenylenediamine (PPD). A positive correlation (P = 0.03) was also detected between avoidance of allergen and improvement of vitiligo lesions.

Causative allergens of ACD may play a role in the development and/or aggravation of vitiligo.