Systematic Review of Lichen Planus Pigmentosus in Children

August 2022 | Volume 21 | Issue 8 | 850 | Copyright © August 2022


Published online July 15, 2022

doi:10.36849/JDD.6760

Krystal Mitchell MD MBAa, Nanette B. Silverberg MDa,b

aDepartment of Dermatology, Icahn School of Medicine at Mt Sinai, New York, NY
bDepartment of Pediatrics, Icahn School of Medicine at Mt Sinai, New York, NY

Abstract
Background: Pediatric lichen planus (LP) is a relatively uncommon condition, with increased presentation in children with darkly pigmented skin.
Objective: To understand the small subset of children with lichen planus (LP) manifesting as lichen planus pigmentosus (LPP), a form with thin plaques and extensive hyperpigmentation, generally in the absence of signs of inflammation
Methods: This article is a systematic review of the English language literature for cases of lichen planus pigmentosus (LPP) in children.
Results: Twenty-one cases were identified including 2 that were linear, 3 inverse types, 1 palmoplantar. In larger series, 2–2.8% of children with lichen planus are affected by this sub-variant. One patient had reported associated oral lesions. Oral and topical corticosteroids, topical tacrolimus, and ultraviolet light have been described as successful therapies.
Conclusions: LPP is an uncommon but important variant of lichen planus in children. In the presence of dark hyperpigmentation of the skin, a biopsy can help identify LPP. Clinicians should be aware that LPP can follow four patterns: common, inverse, palmoplantar, and linear.

J Drugs Dermatol. 2022;21(7):850-853. doi:10.36849/JDD.6760

INTRODUCTION

Lichen planus (LP) is a common inflammatory disorder, with infrequent presentation in children.1 Lichen planus pigmentosus (LPP) is one of the rarest subtypes of pediatric LP, characterized by "dark gray macular pigmentation located on sun-exposed areas of the face, neck, and flexures."2 The majority of LP cases are noted in children of color worldwide. In the United States, there is an over-representation of children who are African American.1 We performed a systematic review of the Lichen Planus Pigmentosus (LPP) in children to better define the entity and clinical appearance.

MATERIALS AND METHODS

A systematic review of LPP in children was conducted as follows: Pubmed search of “lichen planus and children” and “lichen planus pigmentosus and children” was conducted. Table 1 shows the PRISMA flow sheet of the literature search.

RESULTS

Table 2 summarizes the cases.1,3-14, 24 LPP cases were identified in children, 23 in children of color- including 5 South Asians, 1 East Asian, 2 Middle Eastern, 2 Black, and 2 Latin. Sex was reported in 12 children- 7 female, 5 male. The mean age for the 12 children in whom age was reported was 10.67 (range 5-16 years). Distribution subtypes were noted in 21 patients- common type (n=14), inverse (n=3), linear (n=3), palmoplantar (n=1), periorbital (n=1), and oral (n=1).

DISCUSSION

LPP is a form of LP typified by thin violaceous plaques usually of the face and trunk, associated with notable hyperpigmentation and typical histology.8,9,10 Most pediatric LPP cases are reported in children of color (23 of 24, 95.8%; Table 2).

LPP has been previously hypothesized to be a variant of erythema dyschromicum perstans (EDP) and also clinically resembles lichenoid atopic dermatitis. LPP can be distinguished from AD and EDP by location of lesions and histopathology.7,15-17

Distribution of LPP includes common type, inversus, linear, and palmoplantar type. Prior studies demonstrate all linear LP, including linear LPP in childhood, follow the lines of Blaschko.12 A waxing and waning course of lesions are typical.18 In a study of 316 Indian children with LP, 2.8% had the LPP variant.9 Similarly, Kanwar et al reported that 2 of the 100 cases of pediatric LP they reported were LPP sub-variant, a prevalence of 2%.10 LPP appears more commonly in Indian and Middle Eastern populations in all pediatric age groups.3-5,10
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