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Granular Parakeratosis


Granular Parakeratosis

Article Author:
Renee Lucero
Article Editor:
David Horowitz
Updated:
7/10/2020 8:33:38 AM
For CME on this topic:
Granular Parakeratosis CME
PubMed Link:
Granular Parakeratosis

Introduction

Granular parakeratosis is a rare, benign, idiopathic condition that is best categorized as a reaction pattern rather than a distinct disease. The condition presents as red-to-brown scaly-to-hyperkeratotic papules or plaques typically in intertriginous areas. The condition has been reported in patients of all ages and is more commonly seen in women than in men.[1] Granular parakeratosis was originally thought to be a contact dermatitis to personal hygiene products such as deodorants and antiperspirants; however, cases have been reported in the absence of personal hygiene products in the affected areas which discredited contact dermatitis as the etiology.[2] Granular parakeratosis was first described in 1991 by Northcut et al. as "axillary granular parakeratosis."[3] Case reports have also noted granular parakeratosis in other intertriginous areas as well as non-intertriginous body areas such as the face.[4][5] Granular parakeratosis typically self-resolves in one-month to one-year, and responses to various treatments have been inconsistent among reported cases.[6]

Etiology

Granular parakeratosis was first described in the axillae and subsequently described to involve other intertriginous areas.[7][6] The condition was originally thought to be a contact dermatitis to personal hygiene products such as deodorants and antiperspirants; however, cases have been reported in the absence of personal hygiene products in the affected areas, which discredited contact dermatitis as the etiology.[1] The possibility of the condition being an unusual reaction to other topical preparations has not been entirely ruled out as a contributing etiology. Occlusion does appear to be a factor in the etiology of granular parakeratosis, given the predilection for intertriginous areas. Case reports have also noted the resolution of lesions of granular parakeratosis following the elimination of occlusion.[8] Case reports have also noted granular parakeratosis in non-intertriginous body areas such as the face, so occlusion does not appear to be the only etiologic factor.[4][5] Infectious etiologies, such as bacterial or fungal, have had inadequate microbial cultures to support it as an etiology; however, there have been case reports of response to oral antibiotics such as amoxicillin-clavulanate.[9] Given the inconsistent response to various treatments and lack of consistent clinical evidence or patient history, granular parakeratosis is classified as an idiopathic condition.

Epidemiology

Granular parakeratosis has been reported in all ages but is most commonly seen in adults. The condition has a higher prevalence amongst women than men. Granular parakeratosis does not appear to have a geographical or racial predilection. The condition is rare with one study reporting granular parakeratosis being present in only 18 specimens among 363,343 specimens examined.[2] Granular parakeratosis is thought, by some, to be associated with obesity due to the condition being most often reported within intertriginous and occluded body areas.[10] Granular parakeratosis has not been associated with any systemic diseases.

Histopathology

Granular parakeratosis is a rare, benign, idiopathic condition that is best categorized as a reaction pattern rather than a distinct disease. The diagnosis of granular parakeratosis is made by histopathologic evaluation. A punch or shave biopsy should be completed for diagnosis. The confirmation of granular parakeratosis on hematoxylin and eosin (H&E) staining is adequate to confirm the diagnosis. On biopsy, a thickened stratum corneum is noted with abnormal retention of keratohyalin granules as well as an intact stratum granulosum.[2] A biopsy can also delineate if granular parakeratosis is present as a separate reaction pattern or concomitantly present with other treatable conditions such as tinea corporis. On electron microscopy, granular parakeratosis presents as round or stellate keratohyalin granules within the granular layer and retained keratohyalin granules within the corneocytes of the stratum corneum.[11]

History and Physical

Patients with granular parakeratosis typically present with asymptomatic to pruritic papules or plaques in intertriginous areas. Granular parakeratosis can arise over several days to months and presents in areas of previously normal skin.[1] The lesions are typically reddish to brown and present as scaly to keratotic papules that may coalesce into plaques. In adults, granular parakeratosis typically presents in intertriginous areas such as the axillae, submammary folds, abdominal folds, or inguinal folds. In children, two main presenting patterns have been identified. The first clinical pattern described in children presents as linear plaques in the bilateral inguinal folds with a flaky scale. The second pattern described in children presents as geometric plaques in areas of increased pressure during diaper-wearing. Occlusion from diapers does appear to contribute to the presentation of granular parakeratosis in infants; however, the pathogenesis is not clear.[12]

Evaluation

Granular parakeratosis clinically may be confused with several other conditions such as Hailey-Hailey disease, verruca, contact dermatitis, acanthosis nigricans, erythrasma, confluent and reticulated papillomatosis, extramammary Paget disease, amongst others. Granular parakeratosis has also been found to be present concomitantly with other conditions such as tinea corporis. Thus, a punch or shave biopsy should be completed for histopathologic evaluation. The confirmation of granular parakeratosis on hematoxylin and eosin (H&E) staining is adequate to confirm the diagnosis. On biopsy, a thickened stratum corneum is noted with abnormal retention of keratohyalin granules as well as an intact stratum granulosum.[2] A biopsy can also delineate if granular parakeratosis is present as a separate reaction pattern or concomitantly present with other treatable conditions such as tinea corporis.

Treatment / Management

Multiple treatments have been attempted for granular parakeratosis; however, responses to these treatments have been inconsistent amongst reported cases. Given previous thoughts that granular parakeratosis may be an abnormal reaction to personal hygiene products or other topical preparations, discontinuing these topicals as well as prescribing a topical steroid is typically the first attempted management strategy. Topical steroids may decrease pruritus in symptomatic patients; however, reported cases have rarely resolved with topical steroids as monotherapy.[3] One case report noted complete resolution of axillary granular parakeratosis with five days of topical tretinoin 0.025% cream.[1] Another case report noted complete resolution of axillary granular parakeratosis with 10 days of topical calcitriol ointment.[13] Granular parakeratosis has also been reported to respond rapidly to oral isotretinoin in one case report.[14] There has also been one case report of surgical management of submammary granular parakeratosis with elective mastopexy resulting in complete resolution.[8]

Differential Diagnosis

  • Hailey-Hailey disease
  • Verruca
  • Contact dermatitis
  • Acanthosis nigricans
  • Erythrasma
  • Confluent and reticulated papillomatosis
  • Extramammary Paget disease
  • Inverse psoriasis
  • Pemphigus veterans
  • Bowen disease

Prognosis

Granular parakeratosis most often is self-limiting and will resolve in a period of one month to one year.[2][6] However, cases have been reported of granular parakeratosis persisting or chronically recurring for up to 20 years.[15] The condition is not associated with malignancy or any systemic diseases. Obesity and increased occlusion of skin-folds do appear to contribute to granular parakeratosis.

Complications

There have been no reported cases of malignant transformation of granular parakeratosis. Patients with granular parakeratosis may develop secondary overlying bacterial infections, especially in patients with symptomatic pruritic lesions that become impetiginized with scratching. Granular parakeratosis has been found to be concomitantly present with other common skin conditions such as tinea corporis.[2] 

Deterrence and Patient Education

Patients should be educated that granular parakeratosis is benign and often self-resolves. Patients should also be instructed that granular parakeratosis is inconsistently responsive to various treatments, and there is no cure for granular parakeratosis.

Enhancing Healthcare Team Outcomes

Granular parakeratosis is a benign and often self-limiting reaction pattern. Patients can be managed by a dermatologist or dermatology physician assistant or nurse practitioner. Interprofessional communication between providers and pharmacists may improve patient compliance with various treatments for granular parakeratosis. [Level 5]


References

[1] Brown SK,Heilman ER, Granular parakeratosis: resolution with topical tretinoin. Journal of the American Academy of Dermatology. 2002 Nov;     [PubMed PMID: 12399751]
[2] Scheinfeld NS,Mones J, Granular parakeratosis: pathologic and clinical correlation of 18 cases of granular parakeratosis. Journal of the American Academy of Dermatology. 2005 May;     [PubMed PMID: 15858479]
[3] Northcutt AD,Nelson DM,Tschen JA, Axillary granular parakeratosis. Journal of the American Academy of Dermatology. 1991 Apr;     [PubMed PMID: 2033126]
[4] Mehregan DA,Thomas JE,Mehregan DR, Intertriginous granular parakeratosis. Journal of the American Academy of Dermatology. 1998 Sep;     [PubMed PMID: 9738790]
[5] Joshi R,Taneja A, Granular parakeratosis presenting with facial keratotic papules. Indian journal of dermatology, venereology and leprology. 2008 Jan-Feb;     [PubMed PMID: 18187827]
[6] Metze D,Rütten A, Granular parakeratosis - a unique acquired disorder of keratinization. Journal of cutaneous pathology. 1999 Aug;     [PubMed PMID: 10487291]
[7] Wohlrab J,Lüftl M,Wolter M,Marsch WC, Submammary granular parakeratosis: an acquired punctate hyperkeratosis of exogenic origin. Journal of the American Academy of Dermatology. 1999 May;     [PubMed PMID: 10321622]
[8] Nelson G,Lien MH,Messina JL,Ranjit S,Fenske NA, Submammary Granular Parakeratosis Treated With Mastopexy. Journal of drugs in dermatology : JDD. 2017 Aug 1;     [PubMed PMID: 28809996]
[9] Kumarasinghe SPW,Chandran V,Raby E,Wood B, Hyperkeratotic flexural erythema responding to amoxicillin-clavulanic acid therapy: Report of four cases. The Australasian journal of dermatology. 2019 Nov;     [PubMed PMID: 31049927]
[10] Yang JH,Lee HM,Noh TK,Won CH,Chang S,Lee MW,Choi JH,Moon KC, Granular parakeratosis of eccrine ostia. Annals of dermatology. 2012 May     [PubMed PMID: 22577273]
[11] Leclerc-Mercier S,Prost-Squarcioni C,Hamel-Teillac D,Fraitag S, A case of congenital granular parakeratosis. The American Journal of dermatopathology. 2011 Jul     [PubMed PMID: 21587032]
[12] Chang MW,Kaufmann JM,Orlow SJ,Cohen DE,Mobini N,Kamino H, Infantile granular parakeratosis: recognition of two clinical patterns. Journal of the American Academy of Dermatology. 2004 May;     [PubMed PMID: 15097939]
[13] Patel U,Patel T,Skinner RB Jr, Resolution of granular parakeratosis with topical calcitriol. Archives of dermatology. 2011 Aug     [PubMed PMID: 21844474]
[14] Webster CG,Resnik KS,Webster GF, Axillary granular parakeratosis: response to isotretinoin. Journal of the American Academy of Dermatology. 1997 Nov     [PubMed PMID: 9366832]
[15] Reddy IS,Swarnalata G,Mody T, Intertriginous granular parakeratosis persisting for 20 years. Indian journal of dermatology, venereology and leprology. 2008 Jul-Aug;     [PubMed PMID: 18797082]