Skin nontumor

Keratinization disorders

Granular parakeratosis

Resident / Fellow Advisory Board: Caroline I.M. Underwood, M.D.
Shahin Shahsavari, B.A.
Shabnam Momtahen, M.D.

Last author update: 24 April 2023
Last staff update: 24 April 2023

Copyright: 2022-2024,, Inc.

PubMed Search: Granular parakeratosis

Shahin Shahsavari, B.A.
Shabnam Momtahen, M.D.
Page views in 2023: 2,200
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Cite this page: Shahsavari S, Momtahen S. Granular parakeratosis. website. Accessed June 16th, 2024.
Definition / general
  • Granular parakeratosis is an acquired, idiopathic, uncommon, benign, cutaneous condition characterized by scaly eruptions, most commonly in intertriginous areas, with characteristic histopathologic features
Essential features
  • First described in 1991 as axillary granular parakeratosis (J Am Acad Dermatol 1991;24:541)
  • Has been seen in other intertriginous and nonintertriginous regions of the skin
  • Hyperkeratotic flexural erythema
ICD coding
  • ICD-10:
    • L85.8 - other specified epidermal thickening
    • L85.9 - epidermal thickening, unspecified
  • More common in women
  • Intertriginous regions, axilla in particular
  • Nonintertriginous
  • Pathophysiology thought to involve a defective profilaggrin - filaggrin pathway
Clinical features
  • Associations established with metabolic syndrome and obesity
  • Clinically, patients present with erythematous or hyperpigmented papules that may coalesce into plaques
  • Biopsy of the lesion to identify characteristic histopathologic features
Prognostic factors
  • Favorable with self limiting course; resolves in a period of 1 month to 1 year
  • Cases of granular parakeratosis chronically recurring for up to 20 years have been reported
  • Reference: Int J Dermatol 2022;61:973
Case reports
  • 29 year old man with scrotal and groin erythema for 1 month (Clin Cosmet Investig Dermatol 2022;15:1367)
  • 46 year old overweight woman presented with a 2 month history of axillary rash (Cutis 2020;105:E42)
  • 47 year old woman with a 1 week history of asymptomatic, multiple, linear, horizontal, brown, hyperpigmented scaly papules in the infra-abdominal fold (Cureus 2022;14:e24085)
  • 52 year old obese woman with dark brown, scaly, nontender and nonpruritic eruptions in both axillae that gradually had enlarged and thickened over 6 weeks (Cutis 2013;92:61)
  • 52 year old Thai man with multiple tiny filiform hyperkeratotic papules on his face 2 weeks after using antimelasma cream (Skin Appendage Disord 2021;7:144)
  • 85 year old woman with possible varicella zoster infection (S D Med 2021;74:480)
Clinical images

Images hosted on other servers:
Red macules and patches in groin and scrotum

Red macules and patches in groin and scrotum

Hyperpigmented papules in the infra-abdominal fold

Hyperpigmented papules in the infra-abdominal fold

Discrete, tiny, filiform, hyperkeratotic papules on forehead

Discrete, tiny,
filiform, hyper-
keratotic papules
on forehead

Microscopic (histologic) description
Microscopic (histologic) description

Contributed by Shabnam Momtahen, M.D.
Hyperkeratosis, retention of keratohyalin granules, acanthosis Hyperkeratosis, retention of keratohyalin granules, acanthosis Hyperkeratosis, retention of keratohyalin granules, acanthosis

Hyperkeratosis, retention of keratohyalin granules, acanthosis

Sample pathology report
  • Skin, biopsy:
    • Granular parakeratosis (see comment)
    • Comment: Sections show thickened stratum corneum with abnormal retention of keratohyalin granules and parakeratosis. The subjacent epidermis shows acanthosis and mild spongiosis. The findings are compatible with granular parakeratosis.
Differential diagnosis
  • Hailey-Hailey disease:
    • Presence of suprabasilar and intraepidermal cleft along with acantholysis of keratinocytes resembling dilapidated brick wall
    • Absence of retained keratohyalin granules
  • Verruca:
    • Presence of hyperkeratosis, papillomatosis, hypergranulosis
    • Columns of parakeratosis over projecting dermal papillae and intracorneal hemorrhage
    • Vacuolated superficial keratinocytes with pyknotic raisin-like nuclei (koilocytes)
    • Absence of retained keratohyalin granules
  • Contact dermatitis:
    • Presence of prominent spongiosis with parakeratosis, Langerhans cells and superficial perivascular inflammation with eosinophils
    • Absence of retained keratohyalin granules
  • Acanthosis nigricans:
    • Presence of orthokeratotic hyperkeratosis and papillomatosis of stratum spinosum
    • Hyperpigmentation of basal cell layer without melanocytic hyperplasia
    • Absence of retained keratohyalin granules
  • Confluent and reticulated papillomatosis:
    • Presence of hyperkeratosis, papillomatosis, focal acanthosis with increased melanin pigmentation and melanosomes
    • Absence of retained keratohyalin granules
  • Inverse psoriasis:
    • Presence of regular acanthosis, often with elongated rete (psoriasiform), alternating zones of hypogranulosis and hypergranulosis in the epidermis
    • Thinning of the suprapapillary plates
    • Areas of parakeratosis in the stratum corneum with mounds of neutrophils (Munro microabscesses)
    • Perivascular, predominantly lymphocytic infiltrate in the upper and middle portions of the dermis
    • Dilated and tortuous vessels in the dermal papillae
    • Absence of retained keratohyalin granules
Board review style question #1

A 36 year old woman presented to her primary care provider with a 1 month history of axillary erythema, without significant itching, that clinically resembled eczema. The erythema worsened and the skin lesions increased after topical application of steroid ointment. Dermatological examination revealed well demarcated erythema in the axillae with central hyperpigmentation and peripheral dry skin. What is the best diagnosis?

  1. Acanthosis nigricans
  2. Contact dermatitis
  3. Granular parakeratosis
  4. Hailey-Hailey disease
Board review style answer #1
C. Granular parakeratosis. Histological analysis reveals hyperkeratosis and parakeratosis with retention of numerous keratohyalin granules in the stratum corneum. Acanthosis nigricans (answer A) does not show retained keratohyalin granules. Contact dermatitis (answer B) shows prominent spongiosis without retained keratohyalin granules. Biopsy of Hailey-Hailey disease (answer D) shows acantholysis without retained keratohyalin granules.

Comment Here

Reference: Granular parakeratosis
Board review style question #2
A 57 year old woman presented with hyperpigmented, scaly and nonpruritic eruptions affecting the left axilla that have progressively enlarged over the past 4 weeks. There has been no other intertriginous involvement. Her medical history was notable for mild asthma, seasonal allergies and obesity. What is the best diagnosis?

  1. Darier disease
  2. Granular parakeratosis
  3. Seborrheic dermatitis
  4. Warts
Board review style answer #2
B. Granular parakeratosis. Darier disease (answer A) is defined by acantholysis with characteristic dyskeratosis forming corp ronds and grains. Seborrheic dermatitis (answer C) is characterized as acute, subacute or chronic spongiotic dermatitis. Acute form shows spongiosis with overlying scale crust containing a few neutrophils. In subacute lesions, there is psoriasiform hyperplasia with mild spongiosis. Chronic lesions show more pronounced psoriasiform hyperplasia and only minimal spongiosis. Warts (answer D) are defined by the presence of hyperkeratosis, papillomatosis, hypergranulosis; columns of parakeratosis, intracorneal hemorrhage; koilocytes.

Comment Here

Reference: Granular parakeratosis
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