An Overview of Pityriasis Alba

Pityriasis alba is a common, benign skin disorder that typically affects children ages 6 to 12. This condition is characterized by raised, rounded patches of lighter skin that are mainly on the face, although other areas of the body are sometimes involved. Pityriasis alba is so named for its scaly appearance (derived from the Latin word pityrus, meaning bran) and characteristic white patches (alba, for white).

Pityriasis alba causes discolored lesions to develop on the skin. Most often, they are found on the cheeks, but they can also develop on the neck, chest, back, and upper arms.

The spots typically start as pink or red patches that gradually fade into abnormally light patches of skin.

The lesions typically range from a quarter of an inch to an inch in size, with a circular or oval shape. The borders of the lesions are not clearly defined and gradually blend into normally pigmented skin.

The lesions themselves are often raised and may be covered by very fine skin flakes. The scaly appearance is most noticeable during the winter months as a result of drier air. During the summer, the lesions can appear more prominent when other skin is tanned.

The lesions aren't painful, but there may be some mild itching.

Although an exact cause is still unknown, pityriasis alba is thought to be caused when an acute case of dermatitis heals and leaves behind a lighter patch of skin. It may also result from the overuse of topical corticosteroids when treating eczema; this can cause areas of patchy rash to lighten as they heal.

Certain genetic disorders are also believed to cause cutaneous hypopigmentation (loss of skin color) due to the reduced activity of melanocytes, the cells that produce the pigment melanin.

It is estimated that 5% of children in the U.S. will get pityriasis alba at some point in their early school years, according to a 2015 study in the Journal of Clinical Medicine.

Generally, pityriasis alba can be diagnosed with a visual examination and review of your child's symptoms and medical history.

Pityriasis alba is often confused with tinea versicolor in which the overgrowth of fungus on the skin causes patchy white lesions. There are several ways a doctor can distinguish between the two disorders:

• A wood light examination involves the use of a handheld ultraviolet (UV) lamp to highlight differences in skin color. It is usually performed in a dermatologist's office in a darkened room.
• Potassium hydroxide (KOH) can be used to treat a light scraping of the skin. When examined under a microscope, any evidence of fungus will be visibly highlighted, confirming tinea versicolor or other fungal conditions such as tinea corporis (ringworm).

Pityriasis alba can also be confused with vitiligo, a disease caused by the destruction of the melanocytes in the affected skin. Affected skin borders can distinguish the two.

Vitiligo patches initially appear on sun-exposed parts of the body, often after a triggering event such as a sunburn, but can progress to other areas such as the armpits, eyes, groin, genitals, naval, and rectal area. Pityriasis alba also develops on sun-exposed areas, but it isn't clear if sun exposure triggers its development.

Treatment of pityriasis alba is not always necessary. Most cases resolve on their own without it, usually by adulthood. Still, many parents choose to have it treated for cosmetic reasons, especially if their child is self-conscious about their skin.

Even with treatment, recovery can sometimes take several months. The avoidance of tanning (natural or artificial) and the consistent use of sunscreen (minimum 30 SPF) can also help.

Moisturizers that contain emollient ingredients such as petrolatum, mineral oil, squalane, or dimethicone, can help soften the skin and reduce scaliness, especially on the face. Brands that are effective, inexpensive, and easily found include:

• Aquaphor
• Aveeno Cream
• Eucerin

You may also ask your physician for recommendations. Good skin hygiene, in general, can help speed the healing of lesions.

An over-the-counter (OTC) 1% hydrocortisone cream can be used sparingly if there is itchiness. However, care should be taken when using hydrocortisone on the face.

Do not apply around the eyes or on the eyelids. OTC hydrocortisone shouldn't be used for more than four weeks continuously unless under the advice of a doctor.

Because children are more vulnerable to side effects, you should ask your child's doctor before applying hydrocortisone on your child's face and follow their recommendations.

Topical calcineurin inhibitors Elidel (pimecrolimus) and Protopic (tacrolimus) are non-steroidal medications that may also be prescribed to clear the rash. They aren't often needed but are sometimes suggested in more severe cases.

Topical calcineurin inhibitors are used off-label for pityriasis alba. Because they are not steroids, they can safely be used in the eye area.

Anytime your child has an unidentified rash, you should make an appointment with their pediatrician. Pityriasis alba is a harmless condition, and there is no medical reason to treat it. But if doing so will make your child feel more confident, that's a good enough reason to consider it. Remember that, in most cases, pityriasis alba fades by adulthood.