Kératose pilaire

Synonyms: hyperkeratosis, folliculocentric keratotic papules, follicular keratotic papules

Keratosis pilaris is a very common skin condition characterised by the presence of follicular keratotic papules, sometimes associated with baseline erythema on the affected areas. Keratosis pilaris is often described in association with other dry skin conditions.

How common is keratosis pilaris? (Epidemiology)

• It affects nearly 50-80% of all adolescents and approximately 40% of adults.¹

• Most people with keratosis pilaris are asymptomatic and are often unaware of the condition.

• There is no racial bias but females are affected more often than males.

• It tends to present in the first decade of life. It may become worse in adolescence and often improves or disappears in adult life.

• Around half of cases have a positive family history.

• There have been reports of genetic syndromes, such as chromosome 18p deletion, which may manifest as prominent and extensive keratosis pilaris.²

Facteurs de risque

There is an association with ichthyosis and atopy. It tends to improve in the summer. There may be a chronic course of exacerbations and remissions. It is worse with dry skin.

Other associations of keratosis pilaris include scarring alopecia, ectodermal dysplasia, obesity and Down's syndrome.^{1 3}

Keratosis pilaris symptoms³

• There is a rough, goose-flesh appearance of the skin.

• There are small papules of keratosis that are one to two millimetres in diameter.

• There may be some erythema around the lesions or they may be a normal skin colour. A coiled hair may be apparent beneath the papule.

• Pruritus may also be present

• Keratosis pilaris can affect all skin surfaces where hair grows. However, it is more common on the proximal and extensor surfaces of extremities and convex areas such as cheeks and buttocks.

Keratosis pilaris - moderate

By QuarterNotes, CC BY-SA 4.0, via Wikimedia Commons

Diagnostic différentiel

• Acné vulgaire.

• Dermatite atopique.

• Eruptive vellus hair cysts.

• Folliculitis.

• Keratosis follicularis (Darier's disease).

• Kyrle's disease.

• Lichen nitidus.

• Lichen spinulosus.

• Milia.

• Perforating folliculitis.

Enquêtes

The diagnosis is purely clinical and no investigations are required. In very exceptional atypical cases a skin biopsy with histopathological examination may be used to confirm diagnosis.

Keratosis pilaris treatment and management

Current treatment options for keratosis pilaris can temporarily improve the condition although they do not cure it.⁴ Treatment options vary, focusing on avoiding skin dryness using emollients and adding keratolytic agents when necessary.⁵

The British Association of Dermatologists recommends the following:⁴

• Avoid excessive dryness of the skin; emollients and moisturisers can help soften the skin.

• Creams with salicylic acid, lactic acid or urea may be of use in flattening the bumps on the skin

• Expensive cosmetic or vitamin creams have not been shown to be effective.

• An abrasive pad may be helpful.

• Take tepid showers rather than hot baths.

Laser treatment has been shown to lead to significant improvements in skin texture and roughness or bumpiness in keratosis pilaris patients.⁶

Complications

Complications are uncommon. Pigmentary changes and even scarring can sometimes occur.

Pronostic

It often resolves spontaneously over time but there may be exacerbations and remissions over many years. The outcome can be quite variable between cases.