Nevus of Ota (Oculodermal Melanocytosis)
A form of dermal melanocytosis characterized by unilateral, blue-gray or slate-brown hyperpigmentation involving the skin and mucous membranes supplied by the first and second branches of the trigeminal nerve (V1/V2).
Key Clinical Features
- Distribution: Involves the periorbital skin, temple, forehead, malar area, and often the sclera, conjunctiva, and tympanic membrane.
- Appearance: Patchy, mottled gray-blue hyperpigmentation that persists throughout life.
- Demographics: Much more common in Asian populations and in females.
Clinical Significance & Management
| Aspect | Details |
|---|---|
| Malignancy Risk | Low, but there is a small risk of developing uveal or orbital melanoma. |
| Management | Q-switched laser therapy (e.g., Ruby, Nd: YAG) is effective for cosmetic improvement. |
High-Yield Exam Pearl:
- Ocular Involvement: Because of the risk of ocular melanoma and glaucoma, patients with Nevus of Ota require periodic ophthalmologic screening.
- Differentiation: Unlike Mongolian spots, which are lumbosacral and transient, Nevus of Ota involves the trigeminal nerve distribution and is typically persistent.