A birthmark, or naevus, is an area of discoloured skin present on the face or body which is noticeable either at birth or shortly afterwards.

Birthmarks can take a number of forms. Almost everyone, for instance, has moles. Some babies have stork bites, flt red marks on the eyelids, forehead or neck which fade a few weeks after birth.

Many Asian and black babies have blue-black marks at the base of their backs known as Mongolian blue spots, but these usually ddisappear within the first two years of life.

More obvious is the strawberry mark, which is bright red and sometimes protuberant and spongy. Although this mark may appear to increase in area during the infant’s first year, most will gradually break up and disappear before the child’s ninth or tenth birthday.

Some children also have dark brown pigmented marks reffered to as ‘cafe au lait’ spots. Although these marks are usually small and scattered, thet generaally remain for life.

The rarest and most prominent birthmark is the port-wine strain, which is a flat or slightly raised purplish mark that may extend over a relatively large area and which does not fade with time.