What is the classification flow chart for vitiligo?

Vitiligo Classification Flow Chart

Vitiligo is classified into two primary types based on distribution pattern: non-segmental vitiligo (NSV) and segmental vitiligo (SV), which differ fundamentally in their symmetry, progression, and clinical behavior. 1, 2

Primary Classification Algorithm

VITILIGO
    │
    ├─── NON-SEGMENTAL (Type A)
    │    │
    │    ├─── Symmetrical distribution
    │    ├─── Bilateral patches
    │    ├─── Progressive throughout lifespan
    │    ├─── Average onset: 20 years
    │    └─── Common sites: fingers, wrists, axillae, groins, body orifices
    │
    └─── SEGMENTAL (Type B)
         │
         ├─── Unilateral/asymmetrical
         ├─── Confined to one body segment
         ├─── Follows dermatomes or Blaschko's lines
         ├─── Affects younger patients
         └─── Stabilizes within few years

1, 3, 2

Secondary Classification by Disease Activity

Disease activity determines treatment eligibility, particularly for surgical interventions:

• Stable disease: No new lesions, no Koebner phenomenon, no extension of existing lesions for ≥12 months 1
• Progressive disease: New lesions developing, existing patches expanding, or Koebner phenomenon present 4

Tertiary Classification by Extent

Extent of involvement guides treatment selection:

• Localized disease: Limited depigmented areas, amenable to topical therapies 1, 4
• Generalized disease: Widespread involvement (>50% body surface area), requires phototherapy or depigmentation 5, 4

Segmental Vitiligo Subtypes (Trunk-Specific)

For segmental vitiligo on the trunk, six distinct subtypes exist based on anatomical distribution: 6

• Types 1-3: Upper trunk involvement (Type 3 shows characteristic V-shaped pattern, most common at 22.6%) 6
• Types 4-5: Middle trunk involvement (Type 5 shows band-like lateral pattern, 17.9% frequency) 6
• Type 6: Lower trunk/abdomen with rectangular pattern (13.2% frequency) 6

Localized Vitiligo Evolution

Localized vitiligo represents an early, indeterminate stage: 3

• Most localized cases (approximately 34%) eventually progress to non-segmental vitiligo (Type A) 3
• Small subset (approximately 7%) evolves into segmental vitiligo (Type B) within first 12 months 3
• Remaining cases (approximately 59%) may remain localized during observation periods 3

Clinical Diagnostic Pathway

Classical symmetrical presentations can be diagnosed in primary care, while atypical presentations require dermatology referral. 5, 1

• Wood's light examination: Delineates pigment loss, especially in lighter skin types 1, 7
• Thyroid function screening: Essential in all vitiligo patients (34% have autoimmune thyroid disease) 1
• Serial photography: Mandatory for monitoring disease progression 5

Treatment Algorithm Based on Classification

Non-segmental vitiligo:

• Localized: Potent topical steroids (≤2 months) or calcineurin inhibitors 5, 1
• Widespread: Narrowband UVB phototherapy (preferred over PUVA) 5, 1

Segmental vitiligo:

• Requires aggressive early treatment as it stabilizes quickly 1
• Surgical treatments reserved for stable disease (≥12 months stability) 5, 1
• Split-skin grafting superior to minigraft procedures 5

Critical Pitfalls to Avoid

• Never perform surgical interventions on active/progressive disease (contraindicated in disease with progression within 12 months) 5, 1
• Do not extend potent topical steroid use beyond 2 months due to skin atrophy risk 5, 1
• Always screen for thyroid disease given 34% association rate 1
• Do not overlook psychological impact assessment regardless of classification type 5, 1