Nevus of Ota is a skin lesion of blue or gray pigmentation that occurs on the face. The condition is usually congenital, meaning that it occurs before or during birth. In some cases, nevus of Ota may appear in the eye, which usually indicates the presence of ocular disease. The condition goes by several other terms, which include congenital nevus fuscoceruleus ophthalmomaxillaris, melanosis bulbi, oculodermal melanocytosis and oculomucodermal melanocytosis. Nevus of Ota is referred to as nevi of Ota in plural form.
M.T. Ota, known by the pen name Mokutaro Kinoshita, was a Japanese doctor who first described the condition in 1939, which is why it is named after him. The nevi develop from melanocytes, which are the cells in the bottom layer of the epidermis, or the skin's outer layer. Melanocytes are responsible for producing melanin, which provides the skin with its color. Therefore, nevus of Ota occurs when there is hyperpigmentation, or abnormally increased coloration. The cause of this condition remains unknown, though it is known to occur most commonly in Japan, where 1 in every 2,000 people develops it.
Nevus of Ota gradually grows larger in size and darker in color as time passes. Skin-related nevi might be a sign of melanoma, which occurs when melanocytes become malignant and cause skin cancer. Melanoma can also appear in the eyes if it bears the hyperpigmentation. Glaucoma, however, is most commonly associated with eye-related nevi of Ota. Damage to the optic nerve due to this eye disorder can lead to blindness.
The standard, ideal treatment for nevus of Ota is pulsed Q-switched laser surgery. Also known as giant pulse formation, it involves transforming lasers into pulsed output beams targeting the dermal melanocytes. The widespread adoption of Q-switched laser surgery is attributed to its success rate, which is no lower than 90 percent. It is usually administered in four to eight treatments.
Q-switched laser surgery for nevus of Ota has superseded older surgical treatments such as cryotherapy, which involves application of cold to destroy tissue abnormalities, and dermabrasion, which involves wearing away the skin defects with tools and agents such as sandpaper and lasers. Some people use makeup to cover up the blemish, though it is a mere cosmetic rather than medicinal solution. After dermal treatment, no follow-up appointments usually are required and prognosis typically is excellent. People with ocular occurrences, however, might want to regularly visit their ophthalmologists to make sure the condition does not morph into glaucoma or melanoma.