White Patches on Children's Skin in Winter (Pityriasis Alba)
These white patches are pityriasis alba, a benign condition strongly associated with atopic dermatitis and dry skin that becomes more noticeable in winter due to increased xerosis and the contrast created when surrounding skin tans. 1, 2
What Causes This Condition
The hypopigmented patches children develop in winter result from several interconnected factors:
- Atopic diathesis and xerosis are the primary drivers, with pityriasis alba representing a minor diagnostic sign of atopic dermatitis according to established criteria 3, 4, 5
- Dry skin (xerosis) is present in essentially all affected children, and winter weather dramatically worsens this underlying problem 3, 2
- Poor cutaneous hydration appears to be the common pathway leading to inappropriate melanosis and subsequent hypopigmentation 2
- Sun exposure paradoxically makes lesions more visible by creating contrast between normal tanned skin and the hypopigmented patches, which is why parents often notice them more after summer 1, 2
Why Winter Makes It Worse
Winter specifically exacerbates pityriasis alba through multiple mechanisms:
- Cold, dry air removes natural lipids from the skin surface, worsening the baseline xerosis that predisposes to this condition 3
- Indoor heating further dehydrates the skin, compounding the problem 3
- Reduced humidity in winter months prevents adequate skin hydration 2
- The condition affects 5-15% of schoolchildren with atopic backgrounds, making it extremely common 3
Clinical Recognition
These patches have characteristic features that distinguish them from other hypopigmented conditions:
- Finely scaly, hypopigmented patches typically on the face, particularly the cheeks in younger children 4, 1
- More noticeable in children with darker skin types (higher phototypes), though it occurs across all skin types 1, 2
- Associated with general dry skin over the past year, often with other atopic features 3
- Males are affected more frequently than females 1
Management Approach
The cornerstone of treatment is aggressive moisturization with emollients, which should be prescribed in adequate amounts and applied liberally, particularly after bathing. 3
First-Line Treatment
- Liberal use of emollients provides a surface lipid film that retards evaporative water loss from the epidermis 3
- Soap substitutes (dispersible creams) should replace regular soap, as soaps and detergents remove natural skin lipids 3
- Bathing practices should focus on hydrating the skin, with emollients most effective when applied immediately after bathing 3
When Inflammation Is Present
If erythema or scaling accompanies the hypopigmentation:
- Topical corticosteroids (mild to moderate potency) can be used for short periods when inflammation is present 2, 6
- Tacrolimus 0.03% ointment showed superiority over other treatments in achieving repigmentation with limited side effects, applied twice daily for 8 weeks 6
- Calcipotriol 0.005% cream represents an alternative steroid-sparing option 6
Important Caveats
- Avoid excessive bathing and harsh soaps, as these worsen xerosis - the number of daily baths was significantly higher in affected children in one study 1
- Cotton clothing is preferred over wool, which can irritate atopic skin 3
- Extremes of temperature should be avoided as they exacerbate the underlying atopic tendency 3
- This is a benign, self-limited condition that typically resolves with proper skin care and as children age 2, 5
Differential Diagnosis Considerations
While pityriasis alba is the most common cause, other conditions must be excluded:
- Vitiligo shows complete depigmentation rather than hypopigmentation and lacks scaling 7
- Pityriasis versicolor alba can be distinguished by KOH preparation showing fungal elements 2
- Nevus depigmentosus is present from birth and doesn't change with seasons 2
The key message for parents: this is a harmless manifestation of dry, atopic skin that becomes more visible in winter and improves with consistent moisturization and proper skin care. 3, 2