Pityriasis alba is a skin disorder that mostly affects children and young adults. The exact cause is unknown. However, it’s believed that the condition may be associated with eczema, a common skin disorder that causes scaly, itchy rashes.

People with pityriasis alba develop red or pink patches on their skin that are usually round or oval. The patches usually clear up with moisturizing creams or go away on their own. However, they often leave pale marks on the skin after the redness has faded.

People with pityriasis alba get round, oval, or irregularly shaped patches of pale pink or red skin. The patches are usually scaly and dry. They may appear on the:

  • face, which is the most common place
  • upper arms
  • neck
  • chest
  • back

Pale pink or red spots may fade into light-colored patches after several weeks. These patches usually clear up within a few months, but they can last for several years in some cases. They’re more noticeable in the summer months when the surrounding skin becomes tan. This is because the pityriasis patches don’t tan. Wearing sunscreen may make the patches less noticeable in the summer months. The light patches are also more noticeable in people with darker skin.

The exact cause of pityriasis alba isn’t known. However, it’s commonly considered a mild form of atopic dermatitis, a type of eczema.

Eczema may be caused by an overactive immune system that responds to irritants aggressively. The skin’s ability to act as a barrier is reduced in people with eczema. Normally, the immune system ignores normal proteins and only attacks the proteins of harmful substances, such as bacteria and viruses. If you have eczema, however, your immune system may not always distinguish between the two, and instead attack healthy substances in your body. This causes inflammation. It’s similar to having an allergic reaction.

Most people outgrow eczema and pityriasis alba by early adulthood.

Pityriasis alba is most common in children and adolescents. It occurs in approximately 2 to 5 percent of children. It’s most frequently seen in children between the ages of 6 and 12 years. It’s also very common in children with atopic dermatitis, an itchy inflammation of the skin.

Pityriasis alba often appears in children who take hot baths frequently or who are exposed to the sun without sunscreen. However, it’s unclear if these factors cause the skin condition.

Pityriasis alba isn’t contagious.

No treatment is required for pityriasis alba. The patches usually go away with time. Your doctor may prescribe a moisturizing cream or topical steroid cream such as hydrocortisone to treat the condition. In some cases, your doctor may prescribe a nonsteroid cream, such as pimecrolimus. Both types of creams can help reduce skin discoloration and relieve any dryness, scaling, or itchiness.

Even if you’ve had treatment, the patches can return in the future. You may need to use the creams again. In most cases, however, pityriasis alba goes away by adulthood.