eMedicine Specialties > Dermatology > Papulosquamous Diseases

Granular Parakeratosis

Author: Noah S Scheinfeld, MD, JD, FAAD, Assistant Clinical Professor, Department of Dermatology, Columbia University; Consulting Staff, Department of Dermatology, New York Medical College-Metropolitan Hospital; Private Practice
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Updated: Jan 29, 2008

Introduction

Background

Granular parakeratosis, a benign condition, was first described in 1991 as a skin disease manifesting with erythematous hyperpigmented and hyperkeratotic papules and plaques of the cutaneous folds.¹ It is sometimes associated with pruritus. Granular parakeratosis has been associated with excessive use of topical preparations, in particular antiperspirants and deodorants; however, it has been found in persons who have not used such agents. It is also associated with an occlusive environment, increased sweating, and, sometimes, local irritation. Some have linked it to obesity.

Pathophysiology

The etiology of granular parakeratosis is uncertain, but Metze and R ü tten² defended the hypothesis, first proposed by Northcutt et al,¹ that a basic defect exists in the processing of profilaggrin to filaggrin, which maintains the keratohyaline granules in the stratum corneum during cornification. Because granular parakeratosis has been associated with excessive use of topical preparations, an occlusive environment, increased sweating, and, sometimes, local irritation, some suggest that it is an allergic contact or irritant reaction.³ Some patients who have manifested granular parakeratosis have not used topical preparations, and, thus, the causal linkage of granular parakeratosis to topical substances is unclear. The primary cause for this disease remains unknown.

See Contact Dermatitis, Allergic and Contact Dermatitis, Irritant for more information on those topics.

Frequency

United States

Only approximately 40 case reports of this condition have been published, but it is likely more common than the number of case reports suggests. Scheinfeld and Mones⁴ reviewed the diagnoses of 363,343 specimens submitted to the Ackerman Institute of Dermatopathology in New York over a 5-year period. Eighteen (0.005%) of 363,343 specimens were diagnosed with granular parakeratosis. Scheinfeld and Mones⁴ concluded that if the incidence of granular parakeratosis among biopsy specimens is representative of its general prevalence among persons with cutaneous eruptions, the condition is rare.

International

Only rare case reports are noted, but it is probably not a rare condition. In 2002, Rodriguez⁵ reported 3 cases in women in Columbia.

Mortality/Morbidity

Its only associated symptom is pruritus.

Race

No racial association has been reported. Granular parakeratosis has been reported in blacks and whites.

Sex

Most reported cases of granular parakeratosis have occurred in women. Whether this finding represents a reporting bias or a real association is unclear.

Age

Granular parakeratosis has been reported in children,^6,7 but it is mostly reported in women aged 40-50 years.⁸

Clinical

History

Patients present with a 1- to 12-month history of axillary or intertriginous rash. Sometimes, the rash is pruritic; sometimes, it is not.

• In 2005, Scheinfeld and Mones⁴ demonstrated that granular parakeratosis usually occurs in women in their axillae.
• Patients may report a history of applying antiperspirants and deodorants in the immediate period before the rash started. In 2003, Contreras et al⁹ noted that a 70-year-old man reported a burning sensation in the area of granular parakeratosis.
• In another report, mothers reported changing their granular parakeratosis infants' diapers 5-7 times daily. The mothers reported thoroughly washing the area with liquid soap after every diaper change. The mothers also always applied zinc oxide powders and/or pastes to the affected areas.⁶
• In 2002, Rodriguez⁵ reported 3 cases in obese women.
• A number of incidental incidences of granular parakeratosis have been reported, including associations with dermatomyositis¹⁰  and molluscum contagiosum.¹¹ The case of molluscum contagiosum involved a woman with trunk and extremity involvement after a 4-month history of a slowly progressive pruritic papular eruption.

Physical

Granular parakeratosis manifests with intertriginous (ie, groin, intermammary or submammary region, and abdominal folds) bilateral or unilateral brown- or red-crusted patches, papules, or plaques. The rash can be confluent or reticulated. Even when patches or plaques are present, discrete papules can also be present. Granular parakeratosis can appear as slightly erythematous and lichenified plaques.

• In children, granular parakeratosis has been reported to occur in the groin, on the lower back, on the buttocks, and on the flanks.
• Granular parakeratosis reportedly can occur as a solitary keratosis, which is termed granular parakeratotic acanthoma. This appears to be in the same family as acantholytic dyskeratotic acanthoma and epidermolytic acanthoma.¹²
• Granular parakeratosis manifesting as facial keratotic papules has been reported.¹³
• Genebriera et al¹⁴ noted a papillomatous axillary rash due to granular parakeratosis.

Causes

The cause of granular parakeratosis is uncertain. Although controversial, the following have been implicated as etiologies for granular parakeratosis:

• Use of topical solutions or creams, in particular antiperspirants and deodorants¹⁵
• Presence of an occlusive environment
• Increased sweating
• Local irritants

Importantly, because cases have been reported when these factors were not been present, their importance is not clear.

In children, excessive washing has been noted in a series of 4 patients.⁶

Several authors have postulated that in granular parakeratosis, a basic defect exists in the processing of profilaggrin to filaggrin. Filaggrin maintains the keratohyaline granules in the stratum corneum during cornification.

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