Granular Parakeratosis: A Comprehensive Review and a Critical Reappraisal

Granular parakeratosis (GP) is a rare, idiopathic, and benign skin condition that presents classically as erythematous to brown hyperkeratotic papules that can coalesce into plaques. Axillary GP was initially observed by Northcutt and colleagues and has since been described in various other areas of the body including other intertriginous and non-intertriginous sites. The term "granular parakeratosis" is now used to describe not only the skin condition, but also a distinctive histological reactive pattern on biopsy specimens that are either regarded as the disease itself, or merely as an incidental finding. Upon review of the current findings, opinions, and associations of this entity, we propose the reappraisal of GP as a reactive pattern, rather than a distinct entity.