- Jami L Miller, MD
Jami L Miller, MD
- Assistant Professor of Medicine
- Vanderbilt University
Granular parakeratosis (GP) is an uncommon, usually pruritic, benign dermatosis found most commonly in the axillae or other intertriginous areas. The term "granular parakeratosis" is used to describe the distinctive characteristics found on histopathology (parakeratosis and retention of keratohyalin granules in the stratum corneum (picture 1A-B)). (See 'Histopathology' below.)
The clinical findings of GP are also unique, demonstrating erythematous to brown, hyperkeratotic papules that may coalesce into plaques (picture 2A-C). Since the initial description of GP involving the axilla in 1991 , GP has been reported in other intertriginous areas, including inframammary, inguinal, genital, and perianal skin; beneath the abdominal pannus; and in nonintertriginous sites, particularly on the lumbosacral area.
The clinical features, diagnosis, and management of GP will be reviewed here.
GP appears to be uncommon but is likely an underreported diagnosis. In a retrospective study of over 360,000 cutaneous biopsy specimens submitted to a dermatopathology institute, 0.005 percent of specimens had a diagnosis of GP .
GP has been reported more often in women than in men; a higher likelihood for women to seek treatment may be a contributing factor. Most reports describe GP in persons over 40 years of age. However, all age groups may be affected, including children . There is one report of congenital GP .
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