Reliable guideline for children's health
For many parents, noticing white spots on their child's skin can be concerning, often leading to worries about vitiligo. However, pityriasis alba and vitiligo, while both involving white spots, are actually two distinct skin conditions. To help parents better identify them, here are the key differences between the two.
Differences in Clinical Presentation
Vitiligo typically presents as sharply defined, pure white patches. These patches are noticeable, with clear borders and significant pigment loss. The surface of the patches is smooth, without any scaling, and the hair on the affected areas may turn white.
In contrast, pityriasis alba appears as poorly defined, pale white or light pink patches. These patches are usually dry, with fine scales, and tend to be round or oval in shape. The size of the patches can vary, generally ranging from 3 to 5 centimeters in diameter, or even larger.
Differences in Affected Areas
Vitiligo can occur on any part of the body, but it commonly affects exposed areas like the face, neck, and the back of the hands, as well as areas subject to friction or pressure, such as the waist and joints. It may also appear around the mouth, eyes, hands, and near the genitals.
Pityriasis alba, on the other hand, primarily affects the face, though it can also appear on the upper arms, neck, and shoulders.
Differences in Pathology
Vitiligo is caused by the reduction or loss of melanocytes, the cells responsible for producing pigment, leading to depigmentation of the skin.
Pityriasis alba, however, results from the thickening of the skin's outer layer (stratum corneum), mild swelling, and localized pigment reduction, often accompanied by slight dryness and incomplete keratinization of the skin.
Diagnostic Methods and Recommendations
To accurately differentiate between pityriasis alba and vitiligo, doctors often use a Wood's lamp for examination. Under the Wood's lamp, vitiligo lesions appear as pure white patches with sharp borders, in stark contrast to the surrounding normal skin. Pityriasis alba, under the same light, appears as yellowish-white or grayish-white spots.
If parents suspect their child may have vitiligo, it is advisable to not only perform a Wood's lamp test but also consider additional diagnostic methods such as dermoscopy, skin CT, and biopsy to confirm the diagnosis.
Care and Observation
Parents can begin by observing their child's symptoms, ensuring the skin remains moisturized and protected from the sun, and maintaining a balanced diet. If the white patches do not improve within 2 to 3 months, or if they begin to spread or darken, it is essential to seek medical advice from a dermatologist promptly.
