Pityriasis alba

  • Definition
    • Pityriasis alba is a common skin disorder of patches of light-colored (hypopigmented) areas.

  • Causes
    • The cause is unknown but may be linked to eczema and a history of allergies. The disorder is most common in children and teens. It is more noticeable in children with dark skin.

  • Symptoms
    • The problem areas on the skin (lesions) start as slightly red and scaly patches that are round or oval. They usually appear on the face, upper arms, neck, and upper middle of the body. After these lesions go away, the patches turn light-colored (hypopigmented).

      The patches do not tan, but may get red quickly in the sun.

  • Exams and Tests
    • The health care provider can usually diagnose the condition by looking at the skin. Tests, such as potassium hydroxide (KOH), may be done to rule out other skin problems. In very rare cases, a skin biopsy is done.

  • Treatment
    • The provider may recommend the following treatments:

      • Moisturizer to help with the scales
      • Mild steroid creams
      • Medicine called immunomodulator applied to the skin to reduce inflammation
      • Laser treatment

      The patches may clear up, but often return.

  • Outlook (Prognosis)
    • Pityriasis alba usually goes away on its own with patches returning to normal pigment over time.

  • Possible Complications
    • Patches may get sunburned when exposed to sunlight. Applying sunscreen and using other sun protection can help prevent sunburn.

  • When to Contact a Medical Professional
    • Call your health care provider if your child has patches of hypopigmented skin.

  • References
    • Habif TP. Light-related diseases and disorders of pigmentation. In: Habif TP, ed. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 6th ed. Philadelphia, PA: Elsevier Mosby; 2016:chap 19.

      Patterson JW. Disorders of pigmentation. In: Patterson JW, ed. Weedon's Skin Pathology. 4th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2015:chap 10.