Naevi of Ota and Ito
What are naevi of Ota and Ito?
Nevi of Ota and Ito are coloured skin markings of slate-brown or blue/grey colouring. They are unusual birthmarks in which the melanocytes (pigment cells) are found deeper than normal (in the dermis instead of the epidermis). This is also known as dermal melanocytosis.
The difference between a naevus of Ota and a naevus of Ito is its location. Naevus of Ota is on the forehead and face around the eye area; naevus of Ito is on the shoulder and upper arm area.
Naevus of Hori has a similar appearance to the naevus of Ota. However, it is not present at birth, and it often affects both sides of the face.
How do you get naevus of Ota or naevus of Ito, and who is at risk?
It is not known why these naevi occur. Specific mutations have been detected within the dermal melanocytes, most often GNAQ or GNA11.
Naevus of Ota is much more common than naevus of Ito. They are present at birth in 50% of cases but may appear during adolescence or adult life. Thus researchers suggest hormones play a part in their development.
Naevi of Ota and Ito are most commonly found in Asian populations; 0.2-0.6% of Japanese people have nevi of Ota. They appear more frequently in females. Both forms of naevi are uncommon in Caucasians.
What are the signs, symptoms and complications?
Naevus of Ota
- Hyperpigmentation usually located on one side of the face (unilateral) but can be on both sides (bilateral)
- Colour may vary to include brown-violet, violet-blue or blue-green hues
- Hyperpigmentation of parts of the eye may occur: sclera, cornea, iris, retina
- May also involve the inside of the mouth
- Naevi present in childhood may slowly grow and darken until adulthood is reached
- Colour or perceived colour of naevi may change according to personal and environmental conditions, e.g. fatigue, menstruation, hot weather
- If affecting the eye, it rarely cause glaucoma
- Malignant melanoma very rarely develops within dermal melanocytosis, and has usually been reported in Caucasians. Ocular melanoma has been reported in the choroid, brain, orbit, iris, ciliary body, and optic nerve in association with a nevus of Ota.
Naevus of Ito
- Hyperpigmentation located over the shoulder girdle region, usually on one side only
- Possible sensory changes to the involved skin
What treatments are available?
Treatment of a naevus of Ota is usually cosmetic camouflage to cover the disfiguring markings. Laser treatment (usually using 1064nm Q switched Nd:YAG or QS ruby laser) and intense pulsed light (IPL) work by destroying the dermal melanocytes. Multiple treatments are necessary, often with a combination of devices. Laser treatment is more effective in light skinned individuals than in those with dark skin. Unfortunately recurrence is common after laser clearance, sometimes resulting in a darker hue.
If the eye is affected, arrange for regular eye examinations to detect glaucoma. You should see a dermatologist if there is any change in the naevus, especially if you are fair-skinned.
- Book: Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Blackwell Scientific Publications.
On DermNet NZ:
- Birthmarks (naevi)
- Moles (melanocytic naevi)
- Congenital melanocytic naevi
- Blue naevi
- Halo naevi
- Ocular melanoma
- Nevi of Ota and Ito – Medscape Reference