Pigmented contact dermatitis: A brief review

Abstract

Hyperpigmentation is one of the common pigmentary complaints that brings the patient to dermatology services. Though there are multiple etiologies for hyperpigmentation, pigmented contact dermatitis (PCD) remains a common diagnosis. The cosmetics containing dyes, preservatives, fragrances, bactericidal, emulsifiers/surfactants, and vehicles are the potential sources, and paraphenylenediamine, benzyl salicylate, brilliant lake red R, thiomersal and gallate mix are some of the most commonly implicated allergens. The clinical manifestation includes diffuse or patchy brown to blue-black pigmentation of the cheeks, the outer surface of ears, preauricular region, temporal area, nape of the neck, and upper back. Patch testing plays a pivotal role in the diagnosis of PCD and the testing series has to be selected according to the representative population. Given the chronicity of the disease, counseling patients against the use of cosmetics is challenging as the pigmentation tends to persist for longer durations inspite of stopping cosmetics. The pillars of treatment in PCD include recognition of the culprit allergen and preventing further exposure along with pharmacological therapy. This review provides a brief overview and an insight into the etiopathogenesis and management of PCD.

Unveiling the mystery of Riehl's melanosis: An update from pathogenesis, diagnosis to treatment

“…The most common findings are pseudonetwork patterns with brown/gray dots/globules grouped in an arcuate, semiarcuate, or hexagonal way (Honigman & Rodrigues, 2022; Yim et al, 2019). Telangiectatic vessels, tiny scales, perifollicular hypopigmented halos, and follicular keratotic plugs can also be seen (Krueger et al, 2022; Subburaj et al, 2022).…”

“…Prior to the consensus, a new term, acquired dermal macular pigmentation (ADMH) (Chandran & Kumarasinghe, 2016; Subburaj et al, 2022; Vinay et al, 2017, 2021), was coined to include Riehl's melanosis, lichen planus pigmentosus (LPP), ashy dermatoses, and idiopathic macular eruptive pigmentation (IMEP), all of which share significant histopathological and clinical similarities (Bishnoi, Vinay, Arshdeep, et al, 2019; Bishnoi, Vinay, Kumaran, & Parsad, 2019; Vinay et al, 2017).…”

“…In 1970, Osmundsen brought up the conception of pigmented contact dermatitis (PCD) (Rorsman, 1982) as a result of a widespread acceptance that Riehl's melanosis is secondary to contact dermatitis caused by diverse cosmetics, sensitizers, and allergens, which is a noneczematous presentation of contact dermatitis featuring increased pigmentation with minimal or no inflammation (Subburaj et al, 2022). To this day, the conventional view regards Riehl's melanosis and PCD of the face (Daadaa & Tanfous, 2022; Kumarasinghe et al, 2019) as almost identical entities with no discernible distinctions (Sarkar et al, 2022; Sitohang et al, 2020).…”