Pityriasis alba: pale patches on the skin, treatment and causes

BAD says no treatments are usually required. A moisturising cream may be used to improve any dry skin and fine scale. Sunscreens may prevent sunburn and also stop the patches becoming more noticeable by reducing darkening of the surrounding skin. A healthcare professional could suggest steroid creams or ointments if the patches are particularly bothersome.

PCDS advises that in general no treatment is needed or of help, because the condition is self-limiting and the colour returns to normal over a number of months or years. If there is any suggestion of underlying eczema, such as itch, redness and scale, it suggests regular emollients two to three times a day, and if needed a weak topical steroid such as 1% hydrocortisone cream for short periods, or a steroid-sparing treatment such as pimecrolimus cream.

Pityriasis alba is a common skin condition in which pale, slightly scaly patches develop on the skin. BAD explains the name: pityriasis means fine scale and alba means white in Latin. The patches start as scaly oval or round areas and then leave paler areas once the scale has gone.

It is harmless and does not cause permanent changes. The reason it attracts attention is cosmetic and sometimes emotional, because the patches are visible, usually on the face, and can be mistaken for more serious conditions such as vitiligo or a fungal infection.

PCDS describes the aetiology as probably post-inflammatory, possibly following an eczema that is rarely visible by the time the pale patches show. That fits the BAD view of it as a low-grade form of eczema.

PCDS describes several round or oval hypopigmented patches on the face, less well defined than the patches of vitiligo, most often affecting the cheeks. The hypopigmentation can be quite subtle. In some people there is also slight redness and scale, particularly near the nose, which suggests an underlying eczema.

BAD says the patches are accompanied by little or no itch, and are most commonly found on the face and upper body. It notes that the paler areas may be more noticeable in people with richly pigmented skin tones, such as brown or black skin, and may become more obvious after sun exposure and tanning of non-affected skin. PCDS makes the same point that the problem is more apparent in summer, especially in skin of colour, because the patches do not tan as well as the surrounding skin.

• One or several round or oval pale patches, often on the cheeks.

• Fine scale, particularly early on.

• Little or no itch.

• More noticeable in summer and on brown or black skin.

• Usually in children and occasionally young adults.

The British Association of Dermatologists says pityriasis alba resolves by itself gradually and the paler areas return to normal skin with no scarring. Most cases typically return to normal skin tone within months to a year. The Primary Care Dermatology Society says the colour will return to normal over a number of months or years, so it can take longer than a year for some people.

The patches can seem to last longer in summer, because they do not tan as well as the surrounding skin and so become more obvious.

BAD states that the cause is unknown. It is thought to be due to inflammation of the skin and is thought to be a type of low-grade eczema. It is not contagious or hereditary.

The sources do not link pityriasis alba to poor hygiene, diet or any infection. Sun exposure makes it more visible because the surrounding skin darkens while the affected patches do not, but it does not cause the condition.

BAD says it is usually diagnosed by clinical appearance by a healthcare professional and additional tests are not needed. A healthcare professional can often make the diagnosis from the pattern of patches and the age of the person.

PCDS draws a distinction with vitiligo: the patches of pityriasis alba tend to be less well defined, and when a Wood's light is used the hypopigmentation of pityriasis alba is little changed, whereas in vitiligo it becomes more pronounced. Other causes of pale patches, such as fungal infections, may need to be considered if the picture is unclear, and a clinician can advise on whether further assessment is needed.

Pityriasis alba is not an emergency and does not need urgent care. It is reasonable to ask a pharmacist or GP if the diagnosis is uncertain, if the patches are itchy, sore or spreading, if they are not improving over many months, or if they appear in an adult for the first time, since other conditions can look similar.

Parents and young people may also want to talk about how it looks. Because the patches fade, reassurance that it is common, harmless and temporary is often the most useful part of the consultation.

On the NHS, a GP or practice nurse can usually make the diagnosis, and referral to a dermatologist is rarely needed. Moisturisers and sunscreen are inexpensive and available over the counter.

A private dermatology appointment is an option if the diagnosis is uncertain or the skin is very distressing to the person, but the care described by BAD and PCDS is the same in either setting: explanation, skin care and time.