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Synonyms: hyperkeratosis, folliculocentric keratotic papules, follicular keratotic papules
Keratosis pilaris (KP) is a very common skin condition characterised by the presence of follicular keratotic papules, sometimes associated with baseline erythema on the affected areas. KP is often described in association with other dry skin conditions.
- It affects nearly 50-80% of all adolescents and approximately 40% of adults.
- Most people with KP are otherwise 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 KP.
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 KP include scarring alopecia, ectodermal dysplasia, obesity and Down's syndrome.
- 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.
- KP 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.
- The presence of moderate-to-severe KP on the arms is often associated with lower prevalence of acne vulgaris.
Note the slightly raised papules blocked by keratin with surrounding erythema.
- Acne vulgaris.
- Atopic dermatitis.
- Eruptive vellus hair cysts.
- Keratosis follicularis (Darier's disease).
- Kyrle's disease.
- Lichen nitidus.
- Lichen spinulosus.
- Perforating folliculitis.
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.
Current treatment options for KP are limited and are often unsatisfactory to patients.Treatment options vary, focusing on avoiding skin dryness, using emollients and adding keratolytic agents or topical steroids when necessary.
The British Association of Dermatologists recommends the following:
- Avoid excessive dryness of the skin. However, 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.
Laser treatment has been shown to lead to significant improvements in skin texture and roughness or bumpiness in KP patients; however, baseline erythema does not improve with laser treatment.
Complications are uncommon. Pigmentary changes and even scarring can sometimes occur.
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 between cases.
Further reading and references
Thomas M, Khopkar US; Keratosis pilaris revisited: is it more than just a follicular keratosis? Int J Trichology. 2012 Oct4(4):255-8. doi: 10.4103/0974-7753.111215.
Carvalho CA, Carvalho AV, Kiss A, et al; Keratosis pilaris and ulerythema ophryogenes in a woman with monosomy of the short arm of chromosome 18. An Bras Dermatol. 2011 Jul-Aug86(4 Suppl 1):S42-5.
Schmitt JV, Lima BZ, Souza MC, et al; Keratosis pilaris and prevalence of acne vulgaris: a cross-sectional study. An Bras Dermatol. 2014 Jan-Feb89(1):91-5. doi: 10.1590/abd1806-4841.20142399.
Ciliberto H, Farshidi A, Berk D, et al; Photopneumatic therapy for the treatment of keratosis pilaris. J Drugs Dermatol. 2013 Jul 112(7):804-6.
Hwang S, Schwartz RA; Keratosis pilaris: a common follicular hyperkeratosis. Cutis. 2008 Sep82(3):177-80.
Keratosis Pilaris; British Association of Dermatologists
Ibrahim O, Khan M, Bolotin D, et al; Treatment of Keratosis Pilaris With 810-nm Diode Laser: Randomized Clinical Trial. JAMA Dermatol. 2014 Nov 5. doi: 10.1001/jamadermatol.2014.2211.