Pityriasis alba in Adult
Pityriasis alba often has a chronic course, tends to relapse, and usually worsens in the summer with increased sun exposure. It predominately occurs in children between the ages of 3 and 16 years and is found equally in both sexes. In the majority of patients, spontaneous resolution typically occurs before adulthood. Lesions most commonly occur on the face and upper arms. This disorder is common in all ethnicities, although the hypopigmented lesions are more obvious in patients with darker skin phototypes.
The exact cause of the condition is unknown, although the characteristic hypopigmentation may be secondary to a preceding subclinical dermatitis. Environmental triggers such as heat, humidity, sunlight exposure, detergents / soaps, abrasive clothing, chemicals, and smoke, along with stress, may aggravate this disorder. Microorganisms such as Pityrosporum, Streptococcus, Aspergillus, and Staphylococcus may also be triggers. Evidence also suggests that pityriasis alba is a mild eczematous dermatitis.
L30.5 – Pityriasis alba
402296004 – Pityriasis alba
- Extensive cases may resemble the hypopigmented form of tinea versicolor, especially if hypopigmentation involves the face.
- In vitiligo, the patches are completely depigmented and very well demarcated.
- Unlike pityriasis alba, tinea corporis usually has raised borders.
- Topical medication such as retinoic acid, benzoyl peroxide, and potent topical steroids may present in a similar fashion.
- Psoriasis usually has a thicker scale and a more well-defined border than pityriasis alba.
- Atopic dermatitis – Pityriasis alba may be a manifestation of postinflammatory hypopigmentation, seen in individuals with atopic dermatitis.
- Although similar, seborrheic dermatitis is less commonly seen in preschoolers and school-aged children.
- Nummular dermatitis is usually more well defined, the lesions are raised with more prominent scale, and there is intense pruritus.
- Mycosis fungoides, which has a hypopigmented variant, is very rare.
- Tuberous sclerosis usually includes hypopigmented patches on the trunk and presents at birth with associated seizure, intellectual disability, and other skin lesions; shagreen patches and angiofibromas.
- HIV-associated dermatitis
- Leprosy can cause hypopigmented patches.