Introduction
Keratosis pilaris is an extremely common skin condition seen mainly in teenagers and adults that is caused by accumulation of keratin in hair follicles. It is most commonly seen on the extensor surfaces of the upper arms and thighs, but can occur in other locations including the face, chest, buttocks and trunk. It is also sometimes associated with erythema (redness) and pigmentation of the skin on the cheeks of the face (keratosis pilaris rouge).
It is sometimes colloquially known as “Chicken skin” due to its appearance – which can also look a little bit like goosebumps. It occasionally can be itchy.
It often starts in childhood and peaks in adolescence. It is often better in summer and worse in winter.
The diagnosis is clinical and not investigations are required. Occasionally a skin biopsy may be performed if there is doubt about the diagnosis.
It is typically treated with exfoliation (such as a mildly abrasive sponge or scrub in the shower or bath), and if this is unsuccessful then moisturisers that contain urea, salicylic acid, lactic acid or alpha hydroxy acid can be used to break down the keratin. Rarely, topical retinoids may be used.
The condition is not serious and is not infections. It can occasionally lead to scarring and hair loss in the affected areas. It often resolves without treatment in adult life.
Epidemiology
- 80% of adolescents and 40% of adults
- Most patients are unaware or not bothered by the condition
- F > M
Differential diagnosis
Management
There is no cure. Management methods aim to reduce the symptoms, but are only temporary and it often returns when these methods are ceased.
- Avoid excessive dryness of the skin – use a regular emollient (moisturiser)
- Creams continuing urea, salicylic acid or hydroxy acids can reduce the bumps by breaking down the keratin
- Exfoliation with an abrasive sponge or other scrub can reduce the appearance of the bumps
- Laser treatment may be considered
Long term outcome is variable. About half of cases in adolescence will resolve in adult life.
References
- Keratosis Pilaris – dermnet NZ
- Keratosis pilaris – patient.info
- Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
- Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
- Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy