The role of patch and photopatch tests in facial melanoses: A cross-sectional, observational study

Abstract

Background: Facial pigmentation includes various entities such as melasma, lichen planus pigmentosus (LPP), and pigmented contact dermatitis. The pathogenesis may involve certain allergens, which may be responsible for causing a disturbance in the dermoepidermal junction. The elimination of such inciting allergens may aid in the successful treatment of these patients. Objective: The aim was to detect contact allergens with patch and photopatch testing in facial pigmentary disorders. Methods: Fifty patients with facial pigmentary disorders were enrolled. After taking a demographic profile and detailed clinical history and performing an examination, patch and photopatch testing was done using a common suspected allergen series. Results: Out of the fifty patients tested, 28 (56%) showed a positive patch test, while 2 (4%) showed a positive photopatch test. The most common allergen found was a fragrance mix in 17 (34%) patients, followed by paraphenylenediamine (PPD) in 11 (22%). Other allergens showing positivity were nickel sulfate, benzocaine, parthenium, benzophenone-3, octyl methoxycinnamate, etc. Conclusion: Patients with facial pigmentation may have an underlying component of contact dermatitis, which may be a causative or aggravating factor. The avoidance of these allergens may help in increasing the efficacy of treatment in these patients.