Granular Parakeratosis Workup

Updated: Dec 13, 2019
  • Author: Sheevam A Shah, MD; Chief Editor: Dirk M Elston, MD  more...
  • Print

Laboratory Studies

A potassium hydroxide preparation can be used to check for fungal infection.


Other Tests

A Wood lamp can be used to check for erythrasma.



A skin biopsy is the most useful test in establishing the diagnosis of granular parakeratosis.


Histologic Findings

Characteristic histologic findings include psoriasiform hyperplasia, a thickened stratum corneum with retention of keratohyalin granules, and parakeratosis. [13] Most investigators report a well-developed granular layer and a sparse lymphohistiocytic inflammatory infiltrate. The retained granular layer sometimes demonstrates focal vacuolization.

In 2003, Resnik and DiLeonardo [40] described a follicular granular parakeratosis that was a granular parakeratosis confined to the follicle.

In 2004, Resnik et al [41] described dermatophyte-related granular parakeratosis.

Incidental granular parakeratosis has been associated with carcinomas, [42] dermatomyositis, [28] and molluscum contagiosum. [29]

Resnik et al [36] noted the existence of a granular parakeratotic acanthoma.

Yang et al (2012) noted granular parakeratosis of the eccrine ostia. [43]

A study in seven children found preservation of the nuclei and retention of keratohyalin granules from superficial scrapings, which could be used for a novel method of diagnosis. [32]