Nevus of Ota
Nevus of Ota, also called oculodermal melanocytosis, is a benign congenital pigmented lesion made up of blue-gray, blue-black or gray-brown patches that follow the course of the trigeminal nerve (cranial nerve V, branches V1 and V2). It is common in people of Asian descent and typically appears either shortly after birth (about 50% of cases) or around puberty. Women are affected 4–5 times more often than men.
The lesion forms when pigment cells (dermal melanocytes) get held up in the dermis during their migration from the neural crest to the epidermis. At Haute-Derma, nevus of Ota no longer has to be a lifelong cosmetic burden: our ultra-short-pulse picosecond laser protocol breaks up deep dermal pigment effectively, with a very low risk of scarring or loss of pigment.
Causes and Why Nevus of Ota Looks Blue
Nevus of Ota behaves very differently, both biologically and optically, from birthmarks that sit in the epidermis:
- Melanocytes trapped in the dermis: During embryonic development, pigment-cell precursors (melanoblasts) travel from the neural crest to the epidermis. Because of a fault in biological signaling, some of them become "stuck" in the deep and papillary dermis of the skin supplied by branches V1 (eye, forehead) and V2 (cheek, temple, nose).
- The Tyndall effect: Melanin itself is brown or black, yet nevus of Ota looks blue-gray. This is explained by the Tyndall effect: short (blue) wavelengths passing into the dense dermis are scattered back toward the viewer by collagen fibers and deep melanin far more strongly than long (red) wavelengths.
- Effects of hormones and UV: Nevus of Ota often darkens noticeably during menstruation, pregnancy, stress or heavy sun exposure, because dermal melanocytes carry estrogen and progesterone receptors.
Tanino Classification and Clinical Features
The Tanino classification (1939) divides nevus of Ota into four types according to how much of the face is involved:
| Tanino Type | Skin and Mucosa Involved | Eye Involvement |
|---|---|---|
| Type I (mild) | IA: around the eye and eyelids; IB: cheekbone and temple | Faint blue-gray spots on the white of the eye (sclera), or none |
| Type II (moderate) | Eyelids, cheek, temple, root of the nose and forehead | Clearly visible blue spots on the sclera (~60% of cases) |
| Type III (intense) | The whole of one side of the face: forehead, eyelids, cheek, nose, upper lip, temple | Extensive blue discoloration of the sclera, possibly extending to the retina and iris |
| Type IV (bilateral) | Symmetrical on both sides of the face (easily confused with Hori's nevus or deep melasma) | Blue-gray spots on the sclera of both eyes |
Diagnosis and Medical Screening at Haute-Derma
- Clinical Examination and Distinction From Hori's Nevus
- Nevus of Ota: Appears at birth or around puberty, usually on one side of the face, often with blue spots on the sclera and inside the mouth.
- Hori's nevus: Appears later (after age 20), symmetrically on both cheeks, and never involves the eyes or mucous membranes.
- Eye screening: We check for glaucoma. Melanocytes building up in the uvea and the anterior chamber angle can block drainage of the fluid inside the eye, raising eye pressure (in about 10% of patients with nevus of Ota).
- OCT Imaging and Dermoscopy
- Dermoscopy: An even blue-gray area of fine granules or bands, without the pigment network seen in epidermal lesions.
- Skin OCT: Shows elongated, melanin-packed melanocytes scattered between collagen bundles in the mid and deep dermis (200–500 µm).
Picosecond Laser Treatment at Haute-Derma
Because the pigment cells sit so deep in the dermis, peels and creams have almost no effect. The 1064 nm picosecond laser is currently the most effective treatment:
- Photoacoustic shockwave: The 1064 nm wavelength reaches deep into the dermis while being absorbed relatively little by epidermal melanin. With an ultra-short pulse (< 450 picoseconds), the very high peak energy produces a shockwave that shatters dermal melanocytes into tiny particles. Macrophages then clear this pigment debris through the lymphatic system.
- Fine-tuned settings (high fluence, large spot size):
- Spot size: A large spot (6–8 mm) ensures the beam penetrates to the base of the lesion.
- Fluence: 2.0–4.5 J/cm², aiming for the standard clinical endpoint: light grayish-white frosting with mild pinpoint redness and no bleeding.
- Course of treatment: 4–8 sessions, 8–12 weeks apart (the time macrophages need to clear the broken-up melanin). Clearance can reach 90–95%, with a very low risk of textural scarring or loss of pigment.
