Birthmarks, or beauty marks, are very common skin blemishes most likely caused by abnormal blood vessels under the skin, according to Medical News Today. Beauty marks can also become darker or more prevalent with exposure to sunlight, notes WebMD.
Common birthmarks, or vascular birthmarks, and freckles are harmless dark spots found on the body, reports WebMD. Birthmarks are present in a significant portion of newborn babies, and more birthmarks can arise in the early development of the child, or shortly after birth, states Medical News Today. Pigmented birthmarks are a specific branch of the common birthmark; these are caused by the clustering of pigment cells and are usually brown.
Experts say that vascular birthmarks are not hereditary despite the fact that birthmarks are the least prevalent in certain ethnicities, explains Medical News Today. For example, birthmarks are more infrequent in Asian individuals. The most common type of birthmark is known as a "café au lait spot." These spots are present at birth, or shortly after, and are typically oval-shaped with a milky-coffee color. They do not fade with age. One or two birthmarks are common, but if the individual has more than four, he may have a condition called naurofibromatosis, a genetic disorder that affects the nerve tissue.