Pityriasis alba

ANATOMY OR SYSTEM AFFECTED: Arms, back, neck, skin

DEFINITION: A common skin disorder that causes light-colored, scaly patches of skin on the face, neck, and arms

CAUSES: Unknown; related to atopic dermatitis triggered by drying agents (sun, wind, soap)

SYMPTOMS: Light-colored spots on face, neck, arms, and trunk; sometimes itchy

DURATION: A few months to three years, sometimes recurrent

TREATMENTS: Self-resolving; alleviation of symptoms may include moisturizers, mild hydrocortisone cream, phototherapy

Causes and Symptoms

Pityriasis alba is a nonspecific disorder of the skin regarded as a manifestation of atopic dermatitis. It may be triggered by drying agents, including the sun, wind, soap, and bathing. It typically manifests itself on the fragile skin of children between the ages of three and sixteen, usually appearing on the face but sometimes extending to the neck, arms, and of the body. Several patches are typical, extending in diameter from 5 to 30 millimeters. The exact cause is unknown. Although annoying, the disease is not dangerous or contagious.

Pityriasis alba appears as slightly elevated round to oval spots that have little color. The spots are usually white but occasionally pale pink to light brown. The boundaries of the spots are generally uneven and not clearly visible. Being light-colored, the spots are most noticeable in the summertime, standing out from the tanned skin of a patient. As the disorder progresses over a few weeks, the affected areas often develop very fine powdery scales. Dry skin makes the worse.

Treatment and Therapy

Since the disorder eventually resolves on its own in almost all cases, treatment may not be necessary. It is important to keep the skin moisturized. A variety of lotions, creams, or ointments (such as Curel, Nivea, or Lubriderm) may be applied to the affected areas, particularly after bathing or exposure to the sun. If the rash is inflamed or itchy, then a mild cream can be applied daily. For some patients, phototherapy improves the condition.

Pityriasis alba usually clears after a few months, but in some cases it can last up to three years. It typically takes at least several weeks in order for new healthy skin to develop and adjust its color back to normal. In some cases, the disorder will reappear from time to time. Some children experience the disease every summer, but over the years, their skin color eventually returns to normal.

Perspective and Prospects

Pityriasis is derived from the Greek pityron, which means “scales,” while alba means “white.” Therefore, pityriasis alba describes white, scaly patches. The rash is most often confined to the face, especially around the cheeks, mouth, and chin. About 20 percent of the time, it may also occur on the neck, arms, and chest. Occasionally, it may show up only on the arms and trunk of the body.

Care must be taken to distinguish pityriasis alba from other related skin disorders, particularly tinea versicolor and vitiligo. Tinea versicolor, a fungal infection, can be ruled out by examining flakes of skin from the affected areas with a potassium hydroxide test. In vitiligo, there is a well-defined border between normal skin and the diseased spots.

Bibliography

Brannon, Heather. "Pityriasis Alba: White Patches on the Skin." Verywell Health, 3 May 2023, www.verywellhealth.com/pityriasis-alba-1068759. Accessed 7 Apr. 2024.

Choi, Soo Hyen, et al. "Pityriasis Alba in Pediatric Patients With Skin of Color." Journal of Drugs in Dermatology, vol. 22, no. 4, Apr. 2023, p. 417, jddonline.com/articles/pityriasis-alba-in-pediatric-patients-with-skin-of-color-S1545961623P0417X/. Accessed 7 Apr. 2024.

Kimball, Chad T. Childhood Diseases and Disorders Sourcebook: Basic Consumer Health Information About Medical Problems Often Encountered in Pre-adolescent Children. Detroit, Mich.: Omnigraphics, 2003.

Leung, Donald Y. M., and Malcolm W. Greaves, eds. Allergic Skin Disease: A Multidisciplinary Approach. New York: Marcel Dekker, 2000.

"Pityriasis Alba." MedlinePlus, 4 Apr. 2021, medlineplus.gov/ency/article/001463.htm. Accessed 7 Apr. 2024.

Wolff, Klaus et al.. Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology. 7th ed. New York: McGraw-Hill Medical, 2013.