Synonyms: hyperkeratosis, folliculocentric keratotic papules, follicular keratotic papules, ichthyosis vulgaris

Keratosis pilaris (KP) describes a group of disorders.¹ It is a very common condition in which there is hyperkeratosis around hair follicles. KP is often described in association with other dry skin conditions.

Epidemiology

It affects 50-80% of adolescents and around 40% of adults with a positive family history in up to 50%.² It is thought to be inherited as an autosomal dominant disorder of limited penetrance.¹

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

Risk factors

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.

Presentation

• It tends to present in the first decade of life. It may get worse in adolescence and often improves or disappears in adult life.
• There is a rough, goose-flesh appearance of the skin.
• There are small papules of keratosis that are just a millimetre or two 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.
• There is sometimes, but by no means always, associated pruritus.
• The areas usually affected are the back and sides of the upper arms, the cheeks, the front of the thighs and buttocks.²

Differential diagnosis³

• Acne vulgaris.
• Atopic dermatitis.
• Eruptive vellus hair cysts.
• Folliculitis.
• Keratosis follicularis (Darier's disease).
• Erythromelanosis follicularis faciei et colli.⁴
• Kyrle's disease.
• Lichen nitidus.
• Lichen spinulosus.
• Milia.
• Perforating folliculitis.
• Keratosis pilaris rubra.⁵

Associated diseases³

• Vitamin A deficiency (phrynoderma).
• Type 1 diabetes mellitus (ichthyosis and keratosis pilaris).⁶

Investigations

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

Management

There is no cure but the British Association of Dermatologists recommends the following:⁷

• Avoid excessive dryness of the skin but emollients and moisturisers are of limited value. That is not to say that they have no value.
• Creams with salicylic acid, lactic acid or urea may be of value.
• Expensive cosmetic or vitamin creams are not helpful.
• An abrasive pad may be helpful.
• Take tepid showers rather than hot baths.

Calcipotriol is not of value.⁸

Complications

Complications are uncommon pigmentary changes after inflammation and even scarring which can occur.

Prognosis

It often resolves spontaneously with the passage of years but there may be exacerbations and remissions over many years. The outcome can be quite variable.²

Document references

1. Keratosis Pilaris, Online Mendelian Inheritance in Man (OMIM)
2. Poskitt L, Wilkinson JD; Natural history of keratosis pilaris. Br J Dermatol. 1994 Jun;130(6):711-3. [abstract]
3. Alai NN; Keratosis Pilaris, eMedicine, May 2010
4. Augustine M, Jayaseelan E; Erythromelanosis follicularis faciei et colli: relationship with keratosis pilaris. Indian J Dermatol Venereol Leprol. 2008 Jan-Feb;74(1):47-9. [abstract]
5. Marqueling AL, Gilliam AE, Prendiville J, et al; Keratosis pilaris rubra: a common but underrecognized condition. Arch Dermatol. 2006 Dec;142(12):1611-6. [abstract]
6. Pavlovic MD, Milenkovic T, Dinic M, et al; The prevalence of cutaneous manifestations in young patients with type 1 diabetes. Diabetes Care. 2007 Aug;30(8):1964-7. Epub 2007 May 22. [abstract]
7. Patient Leaflet on Keratosis Pilaris, British Association of Dermatologists
8. Kragballe K, Steijlen PM, Ibsen HH, et al; Efficacy, tolerability, and safety of calcipotriol ointment in disorders of keratinization. Results of a randomized, double-blind, vehicle-controlled, right/left comparative study. Arch Dermatol. 1995 May;131(5):556-60. [abstract]

Acknowledgements