Clinical features, histology, and treatment outcomes of granular parakeratosis: a systematic review

Abstract

Background Granular parakeratosis is a rare disorder characterized by erythematousbrown hyperkeratotic papules and erythematous patches with scaling, occurring predominantly in the flexures and sites of occlusion. While the exact underlying pathogenesis remains unknown, there has been a wide variety of precipitating factors and treatment options reported in the literature.Objective We systematically reviewed and identified precipitants of granular parakeratosis, as well as its clinical and histologic features and treatment outcomes.Method A comprehensive literature search was conducted using MEDLINE and Embase in March 2021.Results A total of 60 studies with 129 patients were included for analysis. An inciting factor was identified in 53.4%, the most common being topical agents including zinc oxide (17.1%), deodorant/antiperspirant (15.5%), and those containing benzalkonium chloride (7.0%). The majority presented with bilateral (68.2%) eruption of hyperkeratotic papules or erythematous patches and plaques, most frequently involving the axilla (56.5%). The prevailing histologic feature was retained keratohyalin granules within the stratum corneum in punch biopsy (97.2%) and curette (100%) specimens. Treatment options with reported success ranged from topical corticosteroids and systemic antibiotics to surgical interventions. ConclusionWe provide a systematic review of reported precipitants, clinical features, and treatment options that clinicians should consider when granular parakeratosis is considered.under-reporting in the literature. 4 We systematically reviewed the literature on granular parakeratosis to provide insights into their etiologic factors, clinical features, histologic findings, and treatment outcomes. MethodsThe systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A comprehensive literature search was conducted using MEDLINE and Embase from inception to March 16, 2021, using the terms "granular parakeratosis" or "hyperkeratotic flexural erythema".

A red scaly rash to the groin

“…Granular parakeratosis is often triggered by exposure to a number of topical agents, including zinc oxide, antiperspirants and benzalkonium chlorides (BACs), but may also arise without an identified trigger. 3 There was no history of zinc oxide or antiperspirant use to the groin area in this patient, but it was revealed that her clothing was being washed using laundry products containing BACs.…”

Crusted Papules in the Diaper Region: Answer

“…A systematic review of GP cases found that 43.4% reported topical products as an etiologic factor, most commonly zinc oxide, deodorants/antiperspirants, and benzalkonium chloride-containing products. 1 However, cases have also been reported in the absence of topical exposures, particularly in association with occlusive environments imposed by diapers, sweating, and obesity . One case of congenital GP has also been reported.…”

“…GP can be self-limiting, although recent systematic review found that spontaneous clearing has only been reported in a minority (4.7%) of cases. 1 Elimination of causative agents is generally considered the first line in management in cases where a trigger is identified, but a variety of additional topical and systemic agents have also been used with variable outcomes. In this case, discontinuation of topical zinc oxide along with application of petroleum jelly for skin barrier protection and short courses of topical steroids (hydrocortisone 2.5% ointment in the inguinal region and triamcinolone 0.1% ointment in the perianal region) led to complete resolution.…”

Verrucous Granular Parakeratosis on the Groin: A Case Report

“…With the development of recognition of anatomical distribution, the naming has also evolved. 4 In 1998, Mehregan et al 5 reported a case involving the groin as intertriginous GP, omitting the word “axillary”. In 1999, Metze et al 6 renamed it GP, acknowledging involvement in non-intertriginous areas and omitting the word “intertriginous”.…”

“…Two main lesions types of GP were reported, including erythematous scales and papules (plaques). 4 The first feature of GP is erythematous scales manifested as symmetrical erythema with pathognomonic multi-layer brown epidermal scales. Kumarasinghe et al first proposed the term hyperkeratotic flexural erythema as a better description for this type.…”