Pityriasis alba is a common, benign cutaneous condition that primarily affects children and adolescents, though it can occur in individuals of all ages. It is characterized by the appearance of red, scaly patches on the skin, which later resolve and leave behind areas of hypopigmentation, or lighter skin pigmentation. Although the initial lesions often appear as red, scaly patches, the concern from patients typically arises during the later stage when hypopigmented patches persist. Pityriasis alba is considered to be a manifestation of atopic dermatitis.
Etiology and Pathophysiology
The exact cause of pityriasis alba is unknown, although it is most commonly seen in individuals with a history of atopic dermatitis or other allergic conditions. The condition is thought to result from a combination of genetic predisposition and environmental triggers that affect the skin’s immune response and barrier function. However, pityriasis alba itself is generally considered to be less severe than atopic dermatitis.
Clinical Features
Lesions in pityriasis alba often appear as round, oval, or irregularly shaped patches that may be red, pink, or skin-colored initially. Over time, these lesions evolve into lighter hypopigmented areas, which are typically more noticeable in individuals with darker skin. The patches commonly appear on the face, particularly around the cheeks, and on the arms, and may occur in multiples. The duration of the lesions can vary, ranging from several months to over a year, and they can reappear during different seasons, especially in the summer when individuals with lighter skin tend to tan, making the contrast between affected and unaffected skin more noticeable.
Although the condition is often self-limited, it can recur periodically. Pityriasis alba predominantly affects young children, particularly those under the age of 12, and tends to resolve by adolescence or early adulthood. Importantly, the hypopigmentation associated with pityriasis alba is not permanent and generally fades over time without scarring.
Diagnosis
Diagnosis of pityriasis alba is primarily clinical, based on the characteristic appearance of the lesions and the patient’s history of atopic dermatitis or other allergic conditions. A skin biopsy is rarely necessary. In cases where the diagnosis is uncertain, a biopsy may be performed to rule out other differential diagnoses such as tinea versicolor, vitiligo, or other causes of hypopigmentation.
Treatment and Management
In most cases, pityriasis alba resolves spontaneously without the need for medical intervention. However, treatment may be recommended to alleviate symptoms, improve the appearance of the skin, and prevent recurrence. Emollients such as moisturizers are typically the first-line treatment to maintain skin hydration and support the skin’s natural barrier function. These products are especially beneficial in patients with dry, sensitive skin, as they can help soothe the skin and reduce irritation.
Topical corticosteroids, particularly low-potency options like hydrocortisone, can be prescribed to reduce inflammation and redness associated with the condition. For individuals who experience itching or inflammation, topical corticosteroids can be effective in providing symptomatic relief.
In some cases, nonsteroidal treatments such as pimecrolimus (Elidel) may be used, especially in individuals who have concerns about using corticosteroids or for those who have failed corticosteroid therapy. Pimecrolimus is a topical calcineurin inhibitor that can help reduce inflammation and itching without the potential side effects associated with steroid use. It is FDA-approved for use in patients over the age of 2 and is considered a safe alternative for treating pityriasis alba.
While treatment is often not required, individuals with pityriasis alba should be advised to avoid excessive sun exposure, as sunburn or tanning may exacerbate the contrast between affected and unaffected skin. Photoprotection, such as using sunscreens and protective clothing, may help minimize the appearance of hypopigmented lesions during the summer months.
Prognosis
The prognosis for pityriasis alba is generally favorable, as the condition typically resolves on its own over time, with no long-term consequences. The hypopigmentation usually fades and most individuals outgrow the condition by adulthood. However, some individuals may experience recurrent episodes, particularly during periods of increased skin irritation or exposure to environmental triggers.
Conclusion
Pityriasis alba is a benign, self-limited skin condition that commonly affects children and adolescents, typically in the setting of atopic dermatitis. While it often resolves spontaneously, treatment may be recommended to alleviate symptoms, improve the appearance of the skin, and prevent recurrence. Emollients, low-potency topical corticosteroids, and nonsteroidal treatments such as pimecrolimus are the primary management options. Photoprotection and maintaining skin hydration are key strategies to minimize the visibility of hypopigmented lesions and improve overall skin health.
References
Brodell, R. T., & Finney, R. J. (2006). Pityriasis alba: A common disorder in children. American Family Physician, 73(5), 849-852.
Eichenfield, L. F., & Tom, W. L. (2017). Atopic dermatitis. In Pediatric Dermatology (pp. 321-334). Elsevier.
Pelle, M. T., & Kiehn, S. A. (2015). Treatment of atopic dermatitis. Journal of Clinical and Aesthetic Dermatology, 8(5), 24–30.
