What is the age-wise approach to the workup of hypopigmented (loss of skin color) lesions in children?

Age-Wise Approach to the Workup of Hypopigmented Lesions in Children

The diagnostic approach to hypopigmented lesions in children should be systematically organized by age of onset and extent of lesions, with specific workup tailored to the most likely diagnoses in each age group.

General Approach

• Hypopigmented lesions in children can be categorized based on age of onset (early vs. later childhood) and extent (localized vs. generalized) 1
• Clinical assessment should include visual inspection (which may be aided by dermoscopy) and palpation of the affected areas 2
• Serial photographs are helpful to monitor changes in appearance over time 2
• Wood's light examination is particularly useful for evaluating hypopigmented lesions, especially in fair-skinned patients 3

Infants (0-2 years)

Common Diagnoses

• Tuberous sclerosis complex (TSC)
  • Hypopigmented macules ("ash leaf spots") may not be present at birth but can appear months to years later 4
  • Multiple hypopigmented macules warrant MRI screening for neural involvement 2
  • Requires thorough neurological assessment and family history 2

Diagnostic Approach

• For solitary small or medium hypopigmented lesions without concerning features, referral can be delayed or deferred to primary care 2
• For multiple hypopigmented macules, especially with irregular borders:
  • Consider early referral to pediatric dermatology 2
  • Evaluate for seizures and developmental delays 4
  • Consider "feed and swaddle" technique for MRI in infants under 2-3 months to avoid general anesthesia 2

Preschool Children (3-5 years)

Common Diagnoses

• Pityriasis alba (most common - 24.7% of pediatric hypopigmentation cases) 5
• Nevus depigmentosus 5
• Post-inflammatory hypopigmentation 5
• Vitiligo (onset often in this age group) 5

Diagnostic Approach

• For facial lesions resembling pityriasis alba:
  • Assess for mild scaling and indistinct borders 5
  • Consider topical treatments as first-line therapy 6
• For well-demarcated, stable hypopigmented patches (nevus depigmentosus):
  • Document with photographs 2
  • No further workup typically needed unless associated with other abnormalities 2
• For vitiligo:
  • Perform thyroid function tests including anti-thyroglobulin antibodies 3
  • Document extent with photographs for monitoring 3

School-Age Children (6-12 years)

Common Diagnoses

• Vitiligo (20.4% of pediatric hypopigmentation cases) 5
• Tinea versicolor (6.2% of cases) 5
• Pityriasis lichenoides chronica (PLC) 7
• Leprosy in endemic regions (11.5% of cases in South India) 5

Diagnostic Approach

• For suspected tinea versicolor:
  • KOH preparation of skin scrapings to identify fungal elements 8
  • Dermoscopic examination may show unfocused dotted vessels in hypopigmented background 8
• For PLC with hypopigmented lesions:
  • Consider skin biopsy as these may represent active disease rather than just post-inflammatory changes 7
• For suspected vitiligo:
  • Assess for symmetrical distribution pattern 3
  • Perform thyroid function tests 3
  • Consider screening for other autoimmune conditions 3

Adolescents (13-18 years)

Common Diagnoses

• Vitiligo 5
• Tinea versicolor 5
• Post-inflammatory hypopigmentation 5
• Steroid-induced hypopigmentation 5

Diagnostic Approach

• For suspected vitiligo:
  • Assess for symmetrical distribution 3
  • Perform thyroid function tests 3
  • Document with photographs for monitoring treatment response 3
• For suspected tinea versicolor:
  • KOH preparation of skin scrapings 8
  • Recommend proper cleaning of combs and brushes to avoid reinfection 6

Special Considerations

Congenital Melanocytic Nevi (CMN)

• For solitary small and medium CMN, referral to dermatology can be delayed if no concerning features 2
• For giant CMN or multiple medium CMN with ≥10 "satellite" lesions:
  • Early referral to pediatric dermatology 2
  • MRI screening for neural melanosis 2
  • Monitor for concerning changes (rapid growth, bleeding, pain, nodules, ulceration) 2

Suspicious Lesions

• For any hypopigmented lesion with concerning features (asymmetry, irregular borders, heterogeneous color, large diameter, or evolution), consider skin biopsy 2
• Histopathologic examination of concerning lesions should be performed by a dermatopathologist with expertise in pediatric pigmented lesions 2

Pitfalls to Avoid

• Do not rule out tuberous sclerosis based on absence of hypopigmented macules in infancy, as these may appear later in childhood 4
• Do not assume all hypopigmented lesions in PLC represent post-inflammatory hypopigmentation; they may be active disease requiring treatment 7
• Do not rely solely on clinical appearance for diagnosing epidermodysplasia verruciformis, as lesions can mimic common conditions like pityriasis versicolor 8
• Do not forget to examine the entire skin surface, including scalp, when evaluating for hypopigmented lesions 2