Keratosis Pilaris

Synonyms:KP, 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

It affects 50 to 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 of limited penetrance.¹
There is no racial bias but females are affected more often than males.

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.

• 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 pruritis.
• The areas usually affected are the back and sides of the upper arms, the cheeks, the front of the thighs and buttocks.²

• Acne vulgaris
• Atopic dermatitis
• Eruptive vellus hair cysts
• Folliculitis
• Keratosis follicularis (Darier Disease)
• Erythromelanosis follicularis faciei et colli⁴
• Kyrle disease
• Lichen nitidus
• Lichen spinulosus
• Milia
• Perforating folliculitis
• Keratosis pilaris rubra⁵

• Vitamin A deficiency (phrynoderma)
• Type 1 diabetes mellitus (icthyosis and KP)⁶

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.

There is no cure but the British Association of Dermatologists recommend 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 are uncommon pigmentary changes after inflammation and even scarring can 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.²