Why does pityriasis alba cause white patches on skin?

Pityriasis alba often appears as pale, round or irregular areas with fine scale, commonly on the face, arms, or upper body. The affected skin may have had subtle irritation before the colour change. Dryness and inflammation alter the outer skin surface and the way light is reflected. After the inflammation settles, pigment can take time to return to its surrounding tone.

The contrast may look stronger after tanning because nearby unaffected skin darkens while the patches do not. The patches are usually not sharply chalk-white, and their edges may be soft. A clinician can check the pattern when the diagnosis is uncertain.

Use a gentle, fragrance-free moisturiser regularly and avoid scrubbing, picking, or fragranced products on the patches. Shade and broad-spectrum sun protection reduce tanning contrast and help prevent irritation. If there is itch, redness, or noticeable scale, a clinician may suggest a short course of an appropriate topical treatment. Colour often evens out gradually after the skin calms.

Seek assessment if patches spread quickly, become sharply defined, lose all pigment, bleed, hurt, or involve the eyes or mouth. Arrange a review when the appearance is new and unclear, or when moisturising and gentle care do not improve scale or irritation, because several skin conditions can produce lighter areas.

Ask whether the pattern is consistent with pityriasis alba, whether inflammation or another condition is contributing, and which moisturiser or topical treatment suits your skin. Ask how to protect the area while its colour is returning.