Keratosis pilaris: causes, treatment and how long it lasts

The British Association of Dermatologists (BAD) says treatments do not clear keratosis pilaris completely but can improve it temporarily. Emollients (moisturisers) soften the texture of the skin. Creams containing salicylic acid, lactic acid and/or urea can soften and flatten the bumps, and can be bought over the counter or prescribed. A doctor may sometimes prescribe topical retinoids, which may reduce redness and rough texture.

The NHS says a pharmacist can recommend creams or lotions and can tell you whether you need to see a GP. Both the NHS and the BAD note that other options such as steroid creams, laser treatments, photodynamic therapy, chemical peels and dermabrasion are not usually available on the NHS because they have not been proven to be effective and can be expensive. In many cases the BAD says it may be best to wait for the problem to improve on its own.

The NHS says keratosis pilaris happens when hair follicles become blocked with a build-up of keratin, a substance found in skin, hair and nails. Nobody knows exactly why keratin builds up. The BAD says it appears to be associated with certain genes and that it is harmless and not infectious.

It usually runs in families. The BAD says the inheritance often follows an autosomal dominant pattern, meaning each child of an affected parent has a 1 in 2 chance of inheriting it, and that it may be associated with other skin conditions such as ichthyosis vulgaris and atopic eczema.

The BAD describes keratosis pilaris (KP) as a very common skin condition, typically seen in children and young adults, that is harmless. Keratosis means too much keratin, the protein that protects skin, and pilaris comes from the Latin for hair. Many small plugs, 1 to 2 mm across, block the hair follicles on the upper and outer arms and thighs. It can look like goose bumps, and feel rough.

It usually starts in childhood and becomes more obvious in the teenage years and adulthood. The NHS says it can affect people of any age.

The NHS says you usually get patches of small bumps on your arms, thighs or bottom, though they can appear in other places. The bumps are usually the colour of your skin. They can also be red on white skin, or darker on brown or black skin. The skin can sometimes feel itchy.

The BAD says the skin feels rough and dry and looks as though it has permanent goose bumps, and that some redness may appear around the small bumps. It often gets worse in winter, when skin is drier and rubs more against thick clothing.

The NHS says most people with keratosis pilaris have it for years, and it may eventually clear up by itself. There are things you can do to improve the appearance of your skin.

• Moisturise your skin; ask a pharmacist what is most suitable.

• Use mild, unperfumed soaps and bathing products, or soap substitutes.

• Gently scrub your skin with a washcloth or exfoliating mitt.

• Have cool or lukewarm showers and baths rather than hot ones.

• Do not use harsh scrubs, which can make it worse, and do not scratch, pick or rub the skin.

• Be careful near naked flames if you use emollients: the BAD warns that emollient products can catch fire more easily when in contact with dressings, clothing, bed linen or hair.

The NHS says it can last for a long time, and that most people have it for years before it may eventually clear up by itself. The BAD says it often but not always clears up during adult life. Because it varies with the seasons, many people notice it is better in summer and worse in winter.

The BAD says it is typically seen in children and young adults, and affects more than half of teenagers. It usually starts in childhood. The NHS says that if your child has a rash and you are not sure it is keratosis pilaris, you should look at its information on rashes in babies and children.

The same self-care applies: gentle moisturising, mild soaps and avoiding hot baths. Ask a pharmacist, GP or health visitor before using any active creams on a young child.

The BAD says there are no specific tests and that a doctor can usually make the diagnosis from the typical appearance. A skin biopsy may sometimes help if another condition looks similar.

Speak to a pharmacist if self-help is not working and the condition is bothering you, or if your skin becomes itchy or inflamed. The pharmacist can tell you whether you need to see a GP.

On the NHS, keratosis pilaris is usually managed with self-care and pharmacy or prescribed emollients and creams, as described above. The NHS and BAD both say laser and some other treatments are not usually available on the NHS.

Some people choose private dermatology or aesthetic clinics for laser or peels. Since the BAD says these are not shown to be very effective and can be expensive, ask what results to expect, how many sessions are needed and what they cost in total before agreeing.