Naevus depigmentosus
Naevus achromicus; congenital hypomelanosis; achromic naevus
Naevus depigmentosus is a sporadic congenital hypopigmented patch with poorly-defined borders that is present at birth or appears in early childhood and remains stable in size and appearance throughout life (in proportion to body growth). It is the principal differential of hypomelanotic macules of tuberous sclerosis, piebaldism, vitiligo and hypomelanosis of Ito. Unlike vitiligo, naevus depigmentosus is hypomelanotic (not depigmented), congenital and non-progressive, has no autoimmune background and is not amenable to standard vitiligo therapy. No syndromic or malignant risk. Diagnosis is clinical; treatment is cosmetic only.
Clinical features
- Single well-circumscribed but irregular-bordered hypopigmented patch.
- Present at birth or apparent in early childhood; stable in size relative to body growth; persists lifelong.
- Distribution — trunk most common; can be segmental or whorled (linear naevus depigmentosus along Blaschko lines).
- Wood's lamp — paler patch, but less bright than vitiligo (incomplete melanocyte loss).
- Sporadic — no familial / syndromic association in classical disease.
Classification (Coupe 1976)
- Isolated — single patch.
- Segmental — affects one segment of the body.
- Systematised / linear — along Blaschko lines; consider hypomelanosis of Ito if widespread with extracutaneous features (CNS, ocular, musculoskeletal).
Differential
- Hypomelanotic macule (ash-leaf) of TSC — multiple lesions; family history; other TSC features.
- Piebaldism — bilateral, symmetric, anterior; white forelock; KIT mutation; family history.
- Vitiligo — acquired complete depigmentation; sharp border; bilateral / acral / orificial; autoimmune.
- Hypomelanosis of Ito — extensive along Blaschko lines; CNS / ocular / musculoskeletal anomalies in ~ 75%.
- Naevus anaemicus — pallor due to vascular sensitivity, not pigment loss; does not light up under Wood's lamp.
- Post-inflammatory hypopigmentation — preceding eczema / trauma.
Management
- Reassurance — stable, benign, no malignant or syndromic risk.
- Photoprotection of the depigmented area — reduced melanin photoprotection.
- Cosmetic camouflage — make-up, self-tanning.
- Treatment options for cosmetic concern — Q-switched laser response variable; melanocyte transplantation for stable lesions has been used.
- Counsel about lifelong stability — differentiates from vitiligo.
References
- Coupe RL. Unilateral systematized achromic naevus. Dermatologica; 1967.
- Ezzedine K et al. Pigmentary disorders — review. Lancet; 2015.
Spot a correction?
If any clinical statement, citation or link on this page needs updating, please email admin@skinoncology.net with the page name, the proposed correction and the supporting source.