It is not known why these naevus occur. Specific mutations have been detected within the dermal melanocytes.
Naevus of Ota is common and is 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.
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 QaS 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 clearance, sometimes resulting in a darker hue.
If the eye is affected, arrange for a regular eye examination to detect glaucoma. You should see a dermatologist if there is any change in the naevus, especially if you are fair-skinned.