A birthmark is an irregularity on the skin which is present at birth or appears within the first few months. They are divided into two main types: pigmented and vascular. Pigmented birthmarks are caused by excess pigment cells and are dark in color. Vascular birthmarks are caused by increased or malformed blood vessels and are red or purple in color. They can occur anywhere on the skin. Birthmarks are almost always painless and benign, but can be worrisome and cosmetically bothersome to parents.