Granular parakeratosis

Granular parakeratosis is a rare, benign skin condition characterized by a persistent, scaly rash that typically affects the body's folds, such as the armpits (axillae), under the breasts, and the groin area. First described in 1991, granular parakeratosis is distinguished microscopically by the retention of keratohyalin granules in the stratum corneum, the outermost layer of the skin. This condition is of interest in dermatology due to its unique histopathological features and its sometimes challenging management.

Etiology and Pathogenesis

The exact cause of granular parakeratosis is not fully understood. However, it is thought to result from a defect in the process of keratinization, where the skin fails to shed its outer layer properly. This abnormality leads to the accumulation of keratohyalin granules. Factors that may contribute to the development of granular parakeratosis include irritation from sweat, friction from clothing, and the use of antiperspirants containing aluminum chloride. There is no clear evidence linking it to any infectious agent.

Clinical Features

Granular parakeratosis presents as well-demarcated, hyperkeratotic, red to brown plaques that may be itchy or asymptomatic. The lesions are typically found in the skin folds, with the axillae being the most common site. Although it can occur at any age, it appears more frequently in adults and has a slight predilection for females.

Diagnosis

The diagnosis of granular parakeratosis is primarily based on histopathological examination of a skin biopsy. Characteristic findings include compact hyperkeratosis with retention of basophilic keratohyalin granules in the stratum corneum and a lack of parakeratotic cells. Immunohistochemical staining can help differentiate it from other dermatological conditions.

Treatment

Treatment options for granular parakeratosis are varied and may include topical corticosteroids, retinoids, and calcipotriol, aiming to reduce inflammation and normalize keratinization. In some cases, laser therapy or surgical excision may be considered for resistant lesions. However, recurrence after treatment is not uncommon.

Prognosis

The prognosis for granular parakeratosis is generally good, as it is a benign condition. However, the cosmetic and symptomatic aspects of the disease can significantly impact the quality of life of affected individuals. Ongoing research into the pathogenesis and treatment of granular parakeratosis is essential to improve patient outcomes.

See Also

• Keratinization
• Skin biopsy
• Dermatology
• Hyperkeratosis