Mongolian spots and café au lait marks are both very common birthmarks, caused by the abnormal formation of pigmentation within the skin. They are usually present on the skin from birth, although some may fade on their own while others will grow and darken with time.
Mongolian spots are the most common type of birthmark and are caused by a high concentration of cells that produce pigmentation. They are usually flat marks that are bluish-grey in colour and appear on the lower back or buttocks. Most fade away of their own accord during the first years of life, although in some rare cases, they won’t.
Café au lait macules are brown rather than grey, hence the name. They are hyperpigmented patches of skin that will grow over time and can deepen in colour. They may be present at birth, although they can also appear soon afterwards. Café au lait macules can appear anywhere on the body or face, and while treatment is not necessary, some people may want to seek birthmark removal treatment.
Hyperpigmented lesions can be removed using intense pulsed light, which heats them until the pigments in the skin break down and are absorbed by the body.