Pityriasis Alba

Pityriasis alba is a common, benign, self-limiting skin condition characterized by hypopigmented (lighter) patches. It typically affects children and teenagers (3–16 years) who often have a history of atopy (eczema, asthma).

Onset and Course:

• Primary Complaint: Parents usually notice "white patches on the face".

• Evolution: Lesions often start as slightly pink, dry, scaly patches. The redness fades, leaving behind the paler areas.

• Symptoms: The patches are usually asymptomatic or only mildly itchy.

• Prognosis: It is self-limiting, resolving spontaneously over several months to a couple of years with a gradual return of normal color.

Crucial Note for Darker Skin Tones:

The condition is very common and more noticeable in darker skin tones due to the high contrast. Families often worry it is permanent (e.g., vitiligo), making reassurance that the pigment will return essential.

Lesions:

• • • Morphology: Ill-defined hypopigmented macules or patches (0.5–5 cm, round or irregular). They may have a fine surface scale, which is easiest to see when the skin is gently stretched.

    • Inflammation: By the time of presentation, erythema (redness) is often minimal or absent.

    • Distribution: Face is classic (cheeks, mouth, chin, forehead), but patches are also seen on the neck, shoulders, and upper arms/trunk.

Key Examination Nuances in Darker Skin Tones:

• • • Appearance: Patches are paler than the baseline skin, often appearing soft, chalky, or ash-coloured—they are not stark white (depigmented).

    • Borders: The borders are blurred and ill-defined, unlike the sharply "cut out" appearance of vitiligo.

    • Hair: Hair color is normal in the affected area (distinguishes it from vitiligo).

    • Wood's Lamp: Patches may be more visible but do not show bright white fluorescence like vitiligo.

The core message for Pityriasis alba is that it is benign, cosmetic, and self-resolving. Treatment is mainly supportive to minimize dryness and scale, and to reduce the visual contrast.

1. General Skin Care (First-line):

• Emollients: Apply bland emollients daily to reduce dryness and scaling.

• Avoid Irritants: Use gentle, non-soap cleansers and avoid harsh detergents or fragranced products.

2. Sun Protection (Crucial for All):

• Apply daily broad-spectrum SPF 30 to the face and exposed areas.

• This is vital because reducing the tanning of the surrounding skin lessens the contrast, making the hypopigmented patches less obvious.

3. Topical Therapy (If Redness/Itch is Present):

• A short course of a low-potency topical steroid (e.g., hydrocortisone 0.5–1%) once or twice daily for up to 1–2 weeks can be used if there is persistent redness or mild itch, and then stopped.

• Continue emollients long-term.

Counselling for Families (Especially Darker Skin Tones):

• Reassure that the condition is not contagious, not scarring, and the pigment almost always returns to normal, but slowly (think months, not days).

• Caution families against over-treating with strong steroids or unnecessary bleaching agents, which could cause true and permanent dyspigmentation.

Skinsight – Pityriasis Alba: https://skinsight.com/skin-conditions/pityriasis-alba/

NCBI Bookshelf – Pityriasis Alba (StatPearls): https://www.ncbi.nlm.nih.gov/books/NBK431061/

DermNet NZ – Pityriasis Alba: https://dermnetnz.org/topics/pityriasis-alba/