What are the different kinds of birthmarks?

The various birthmarks are categorised on the basis of the type of cell they originate from; the most common ones are either derived from blood vessels or pigment forming cells.

Birthmarks derived from pigment forming cells-
- Congenital Melanocytic nevi: The birthmarks with excess pigment forming cells in the superficial layer of skin present themselves as black coloured flat or raised birthmarks termed as Congenital Melanocytic nevi. They are quite common and can develop at birth or may develop in childhood. They are usually too small to warrant any treatment. Rarely, these moles can be big enough to cover more than half of the body. These are usually persistent and grow proportionate to body size.
- Mongolian spots: The birthmarks with excess pigment forming cells in the deeper layer of the skin appear as blue or purple coloured flat birthmarks known as Mongolian spots. They are very common, seen in 80% of dark-skinned babies, usually in Indians and Mongolians. They are generally present at birth and occur most commonly on the lower back. Mongolian spots usually fade with time, mostly before ten years of age; however in few cases, they might stay for a lifetime.
- Nevus of Otta: When similar blue coloured birthmarks are present on the face around the eye, then they are called Nevus of Otta.
- Café-au-laitt macules: Defective pigment forming cells in the superficial layer of skin can lead to light brown coloured birthmarks called as café-au-laitt macules. These are usually round or oval blended coffee-colored patches on the skin which are persistent and asymptomatic. One need not worry as long as they are few and small in size. However, if these spots are large and are more than six in number, they can be associated with other developmental abnormalities.
- Nevus Depigmentosus: Absence of pigment-forming cells in the superficial layer of skin leads to a white coloured flat patch called as Nevus Depigmentosus. They also stay all through your life. Sometimes, the hair over these white patches is also light coloured giving a striking contrast, especially in the Indian skin. But the good news is that they do not spread to other sites and are not associated with any complication.
Birthmarks derived from blood vessels-
- Portwine stain or Stroke bite: Red coloured flat or raised birthmarks are usually a Portwine stain or Stroke bite made up of dilated blood vessels. These are commonly found on the head and neck area and appear as a flat pink area at the time of birth that gradually deepens in colour and become raised. Few of them disappear by the age of two years, but most of them stay and become quite disfiguring.
- Hemangioma: Red-colored raised and globular masses are usually Hemangioma filled with bunches of proliferating blood vessels. Hemangiomas appear similar to Portwine strain at birth, but they grow very fast and turn into globular masses in a year or two. The Hemangioma near eyes, nose or ears can disturb vision, breathing, and hearing respectively. However, they usually start regressing by five years of age and eventually disappear.

Besides these most common birthmarks, there are hundreds of rare forms, description of which is beyond the scope of this article.