Nevus unius lateris

Nevus unius lateris is a rare type of birthmark that is present at birth or appears within the first or second year of life. It is characterized by an extensive network of small, darkly pigmented spots and patches that cover one side of the body and follows a dermatomal distribution.

Characteristics

The birthmark is usually unilateral, covering one side of the body, but can also be bilateral in rare cases. The lesions are typically brown to black in color and vary in size. They can be flat or slightly raised and may have a rough or smooth surface. The distribution of the lesions follows the lines of Blaschko, which are invisible lines on the skin that represent the paths of embryonic cell migration.

Etiology

The exact cause of Nevus unius lateris is unknown. However, it is believed to be a mosaic disorder, which means it is caused by a mutation that occurs after fertilization and affects only a portion of the body's cells. This mutation is not inherited from the parents and is not likely to be passed on to offspring.

Diagnosis

Diagnosis of Nevus unius lateris is primarily based on the characteristic appearance of the lesions and their distribution pattern. In some cases, a skin biopsy may be performed to confirm the diagnosis and rule out other conditions.

Treatment

There is no cure for Nevus unius lateris, and treatment is primarily aimed at managing symptoms and preventing complications. This may include the use of topical medications to reduce itching and inflammation, and laser therapy or surgery to remove or reduce the appearance of the lesions.

Prognosis

The prognosis for individuals with Nevus unius lateris is generally good. However, there is an increased risk of developing skin cancer, particularly melanoma, in the affected areas. Regular skin examinations are recommended to monitor for changes that may indicate the development of skin cancer.

See also

• Nevus
• Birthmark
• Dermatology
• Mosaicism