Home Translating Report News Physicians Diseases Body Sites Lab tests Search
Home Diseases and Health Information


This is a rare and distinctive skin rash that occurs in the axillary and occasionally in the submammary regions. It is characterized by erythematous hyperkeratotic plaques and papules. Although the cause is unknown, it is thought to represent an unusual reaction to topical anti-perspirants.


Disease Associations  
Gross Appearance and Clinical Variants  
Histopathological Features and Variants  
Differential Diagnosis  
Commonly Used Terms  
Internet Links  

Incidental Granular Parakeratosis Associated With Dermatomyositis.

Pock L, Hercogova J.

*Dermatopathologic Laboratory, Prague, Czech Republic daggerDepartment of Dermatology and Venereology, 2nd Medical Faculty, Charles University, Prague, Czech Republic
Am J Dermatopathol. 2006 Apr;28(2):147-149. Abstract quote  

A 43-year-old patient presented with a 4-month history of intermittently occurring symmetrical and slightly scaling erythematous plaques in his zygomatic regions.

Because of polymyositis in the patient's history, the skin lesions were thought to be a manifestation of dermatomyositis. The skin biopsy revealed a sparse superficial perivascular infiltrate of lymphocytes, which was associated with telangiectases and both discrete vacuolar alteration and smudging of the dermal-epidermal junction. These findings were consonant with dermatomyositis. In addition to these features focal granular parakeratosis was present.

The histopathologic presence of granular parakeratotic corneocytes above a zone of orthokeratosis and the absence of clinical features of granular parakeratosis indicate the granular parakeratosis is incidental.

Dermatophyte-related granular parakeratosis.

Resnik KS, Kantor GR, DiLeonardo M.

Institute for Dermatopathology, Conshohocken, PA 19428, USA
Am J Dermatopathol. 2004 Feb;26(1):70-1. Abstract quote  

A patient presented with a two-month history of an annular eruption on her back. Biopsies of this process revealed dermatophytosis and concurrent granular parakeratosis.

This patient's eruption resolved completely with antifungal therapy suggesting that the fungal organisms caused the granular parakeratosis.
Incidental Granular Parakeratosis Associated With Molluscum Contagiosum.

Pock L, Cermakova A, Zipfelova J, Hercogova J.

From the *Dermatopathologic Laboratory, 2nd Medical Faculty, Charles University, Prague, Czech Republic; daggerDepartment of Dermatology, Znojmo; double daggerDepartment of Dermatology, Moravsky Krumlov; and section signDepartment of Dermatology and Venereology, 2nd Medical Faculty, Charles University, Prague, Czech Republic.

Am J Dermatopathol. 2006 Feb;28(1):45-47. Abstract quote  

A patient presented with a 4-month history of slowly progressive pruritic papules on her trunk and extremities.

Biopsies from 2 of these lesions revealed molluscum contagiosum. One of the biopsies also showed several small foci of granular parakeratosis.

Based on the clinical features and course of this patient, the granular parakeratosis seems to be an incidental finding.
Incidental Granular Parakeratosis Associated with Molluscum Contagiosum.

Lumir P, Alena C, Jindra Z, Jana H.

From the *Dermatopathologic Laboratory, 2nd Medical Faculty, Charles University, Prague, Czech Republic; daggerDepartment of Dermatology, Znojmo; double daggerDepartment of Dermatology, Moravsky Krumlov; section signDepartment of Dermatology and Venereology, 2nd Medical Faculty, Charles University, Prague, Czech Republic.
Am J Dermatopathol. 2005 Jun;27(3):255-257. Abstract quote  

A patient presented with a 4-month history of slowly progressive pruritic papules on her trunk and extremities. Biopsies from 2 of these lesions revealed molluscum contagiosum. One of the biopsies also showed several small foci of granular parakeratosis.

Based on the clinical features and course of this patient, the granular parakeratosis seems to be an incidental finding.



Granular parakeratosis - a unique acquired disorder of keratinization.

Metze D, Rutten A.

Department of Dermatology, University of Munster, Germany.

J Cutan Pathol 1999 Aug;26(7):339-52 Abstract quote

Axillary granular parakeratosis is a recently described condition presenting with erythematous hyperkeratotic papules and plaques.

We report on nine women and one man with eruptions not only localized to the axillae. Biopsy specimens were investigated by histology, immunohistochemistry, electron microscopy, immuno-electron microscopy, and in situ hybridization.

In general, the epidermis was hyperplastic and showed a well preserved stratum granulosum. In the upper dermis a discrete perivascular CD4+ T-cell infiltrate was found, CD1+ dendritic cells were absent from the epidermis. The distribution pattern of the epidermal keratins (keratin 5/14, 1/10) and the expression of involucrin was regular. The horny layer was excessively thickened and parakeratotic. The nuclear remnants showed marginal chromatin condensation and were reactive for the nick-end labeling technique using TdT-mediated dUTP-biotin. The corneocytes were characteristically replete with basophilic granules which showed both ultrastructural features of keratohyalin granules and immunoreactivity for filaggrin. Loricrin was expressed irregularly in small L-granules.

Granular parakeratotic cells revealed regular development of a cornified envelope while cell membranes and desmosomes remained undegraded. In conclusion, our studies on granular parakeratosis suggest a basic defect in processing of profilaggrin to filaggrin that results in a failure to degrade keratohyalin granules and to aggregate keratin filaments during cornification. Associated abnormalities of the cell surface structures and dysregulation of cornified envelope components may account for the retention hyperkeratosis.

Further studies are necessary to clarify the etiology of this unique, acquired disorder of keratinization that localizes to intertriginous areas and body folds.



Axillary granular parakeratosis.

Kossard S, White A.

Skin and Cancer Foundation Australia, Darlinghurst, NSW, Australia.

Australas J Dermatol 1998 Aug;39(3):186-7 Abstract quote

A 54-year-old woman had a 3 year history of a recurrent bilateral axillary rash during the summer months. Both axillae showed hyperkeratotic, fissured and cobblestone plaques. Skin biopsy showed the histology previously defined as axillary granular parakeratosis.

This finding may indeed represent an unusual contact reaction to anti-perspirants interfering with epidermal keratinization.


Submammary granular parakeratosis: an acquired punctate hyperkeratosis of exogenic origin.

Wohlrab J, Luftl M, Wolter M, Marsch WC. Department of Dermatology, Martin-Luther University, Halle-Wittenberg, Halle (Saale), Germany.

J Am Acad Dermatol 1999 May;40(5 Pt 2):813-4 Abstract quote

Granular parakeratosis is a histologic phenomenon that produces a characteristic clinical picture with multiple brownish and hyperkeratotic papules. In all 6 published cases of localized axillary parakeratosis, excessive use of different topical preparations (cream-type products, deodorants that include roll-on and stick types, antiperspirants, shampoos, bath soaps) was reported by the authors. The exact pathogenic causal relationships have not yet been resolved.

In the case reported below, we demonstrate for the first time that the macro- and micromorphological entities can also occur in the submammary region.


Granular parakeratosis: pathologic and clinical correlation of 18 cases of granular parakeratosis.

Scheinfeld NS, Mones J.

St Lukes Roosevelt Hospital Center and The Ackerman Institute of Dermatopathology, New York, New York 10025, USA.
J Am Acad Dermatol. 2005 May;52(5):863-7. Abstract quote  

BACKGROUND: Granular parakeratosis (originally termed axillary granular parakeratosis) is an idiopathic, benign, nondisabling cutaneous disease that manifests with intertriginous erythematous, brown or red, scaly or keratotic papules and plaques. It presents in all age groups and has no established clinical associations.

OBJECTIVES: We wanted to assess the following: (1) the incidence of granular parakeratosis in biopsy specimens; (2) the differential diagnosis submitted with specimens requisition of granular parakeratosis; and (3) variations in its histopathology.

METHODS: Between July 1, 1999 and December 31, 2003, 363,343 specimens were submitted to The Ackerman Institute of Dermatopathology in New York. A computer search was done of these specimen records and cases diagnosed with granular parakeratosis were reviewed. A thickened stratum corneum with retention of keratohyalin granules was considered diagnostic of granular parakeratosis.

RESULTS: Eighteen of 363,343 specimens (0.005%) were diagnosed with granular parakeratosis. The diagnosis was confirmed by re-review of specimens. All lesions were located in the axillae. All patients were adults; most were women. In only one instance was the correct clinical diagnosis of granular parakeratosis submitted with a biopsy requisition of it.

Granular parakeratosis is rare, if its incidence among biopsy specimens is representative of its true prevalence. The failure to include granular parakeratosis on biopsy requisition forms of granular parakeratosis specimens indicates that dermatologists are not familiar with it. Variations of the histopathology of the 18 cases occurred but did not correlate with the clinical impressions included on biopsy requisition forms.

Granular parakeratosis: a case report and literature review.

Wallace CA, Pichardo RO, Yosipovitch G, Hancox J, Sangueza OP.

Department of Dermatology, and Department of Pathology, Wake Forest University Baptist Medical Center, Winston-Salem, NC, USA.

J Cutan Pathol. 2003 May;30(5):332-5. Abstract quote

BACKGROUND: Granular parakeratosis is suspected to result from an error in epidermal differentiation, leading to variably pruritic, hyperpigmented-to-erythematous patches and plaques. Characteristic histopathologic features include a thickened stratum corneum, compact parakeratosis with retention of keratohyalin granules, vascular proliferation, and ectasia. The pathogenesis of this entity is uncertain.

METHODS: We present a case of axillary granular parakeratosis and review the literature.

RESULTS: The lesion showed a thickened stratum corneum with compact parakeratosis, slight epidermal hyperplasia, and a sparse perivascular lymphohistiocytic infiltrate. Keratohyalin granules were diffusely present within the parakeratotic stratum corneum, and the retained granular layer showed focal vacuolization.

CONCLUSIONS: Granular parakeratosis is a rare form of parakeratosis most often seen in the axilla, although other intertriginous areas may be affected. Unique histopathologic findings allow for a specific diagnosis to be made. Although an irritant contact reaction appears causative, mechanical irritation may also play a role in inducing these skin changes.

Axillary granular parakeratosis.

Northcutt AD, Nelson DM, Tschen JA.

Department of Pathology (Dermatopathology Section), Baylor College of Medicine, Houston, TX.

J Am Acad Dermatol 1991 Apr;24(4):541-4 Abstract quote

The term axillary granular parakeratosis is proposed for a unique axillary eruption with distinct histopathologic features.

Four middle-aged to elderly patients (three women, one man) had unilateral or bilateral, usually pruritic, hyperpigmented to bright red patches in the axillae. Biopsy specimens revealed severe compact parakeratosis with the stratum corneum measuring 80 to 250 microns in maximal thickness, maintenance of the stratum granulosum, remarkable retention of keratohyaline granules throughout the stratum corneum, and vascular proliferation and ectasia.

A contact reaction to an antiperspirant/deodorant is suspected as the cause. We speculate that the offending agent alters the maturation sequence of the stratum granulosum and stratum corneum, possibly by interfering with the degradation of filaggrin precursor to filaggrin units.

Axillary granular parakeratosis.

Mehregan DA, Vandersteen P, Sikorski L, Mehregan DR.

Pinkus Dermatopathology Laboratory, P.C., Monroe, Michigan 48161, USA.

J Am Acad Dermatol 1995 Aug;33(2 Pt 2):373-5 Abstract quote

We report two cases of axillary granular parakeratosis, which is a unique eruption involving the axilla that has distinctive histopathologic features.

Both of our patients had slightly pruritic, hyperpigmented patches in the axilla. The biopsy specimens revealed severe compact parakeratosis with maintenance of the stratum granulosum and retention of keratohyalin granules throughout the stratum corneum, which was markedly thickened and measured between 90 to 185 microns.

The exact etiology is not known, but this conditions is believed to represent a contact reaction to an antiperspirant or deodorant.


Follicular granular parakeratosis.

Resnik KS, DiLeonardo M.

Institute for Dermatopathology, Conshohocken, Pennsylvania 19428, USA.

Am J Dermatopathol. 2003 Oct;25(5):428-9. Abstract quote  

An 83-year-old patient presented herself with a ten-year history of keratotic papules on her trunk. A biopsy of this process revealed granular parakeratosis confined to the infundibulum of a follicle.

Exclusive follicular involvement in granular parakeratosis has not been previously described.

Granular parakeratotic acanthoma.

Resnik KS, Kantor GR, DiLeonardo M.

Institute for Dermatopathology in Conshohocken, Pennsylvania 19428, USA.

Am J Dermatopathol. 2005 Oct;27(5):393-6. Abstract quote  

Granular parakeratosis was originally described as a dermatosis confined to the axillae that histopathologically shows characteristic findings in the cornified layer consisting of parakeratotic corneocytes housing keratohyaline granules.

Since the original description of this entity, non-intertriginous examples and even incidental foci of granular parakeratotic corneocytes in association with other dermatoses have been recognized.

This report details the findings of a previously unreported entity that we are naming granular parakeratotic acanthoma, which is fundamentally akin to acantholytic dyskeratotic acanthoma and epidermolytic acanthoma (ie, a solitary keratosis that histopathologically displays features indicated in its name).



Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Ninth Edition. Mosby 2004.
Sternberg S. Diagnostic Surgical Pathology. Fourth Edition. Lipincott Williams and Wilkins 2004.
Robbins Pathologic Basis of Disease. Seventh Edition. WB Saunders 2005.
DeMay RM. The Art and Science of Cytopathology. Volume 1 and 2. ASCP Press. 1996.
Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
Fitzpatrick's Dermatology in General Medicine. 6th Edition. McGraw-Hill. 2003.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

Commonly Used Terms

Basic Principles of Disease
Learn the basic disease classifications of cancers, infections, and inflammation

Commonly Used Terms
This is a glossary of terms often found in a pathology report.

Diagnostic Process
Learn how a pathologist makes a diagnosis using a microscope

Surgical Pathology Report
Examine an actual biopsy report to understand what each section means

Special Stains
Understand the tools the pathologist utilizes to aid in the diagnosis

How Accurate is My Report?
Pathologists actively oversee every area of the laboratory to ensure your report is accurate

Got Path?
Recent teaching cases and lectures presented in conferences

Internet Links

Pathologists Who Make A Difference
Search for a Physician Specialist

Last Updated April 27, 2006

Send mail to The Doctor's Doctor with questions or comments about this web site.
Read the Medical Disclaimer.

Copyright The Doctor's Doctor