Our bodies are dappled with all sorts of spots – freckles, moles, and the odd pimple or scar. Most of our skin's spots we acquire as we get older or are exposed to the sun. Some appear on our skin before we even emerge from the womb.

Birthmarks are unique marks of all shapes and sizes that have no apparent cause or purpose. Some remain all our lives. Some fade. Some don't even develop until weeks or months after an infant is born. Not all of us have birthmarks. For those of us who do, birthmarks cannot be prevented but some of them can be treated, removed, or camouflaged.

Birthmarks fall into two main categories: pigmented birthmarks and vascular birthmarks. And there are several types of each variety.

Pigmented birthmarks

Pigmented birthmarks are those that appear when there is a concentration of pigment in one area of skin. These include café-au-lait spots and several types of moles.

  • Café-au-lait spots
    These common, permanent birthmarks take their name from the way they look on light-coloured skin - light brown like the colour of coffee with milk or cream. On darker skin, the spots appear darker. Café-au-lait spots are often oval in shape, but this may vary. Most café-au-lait spots are harmless and require no treatment. However, an infant born with more than six café-au-lait spots may need further evaluation, as there may be an underlying genetic condition.

  • Moles
    Moles usually develop after sun exposure (not considered a birthmark), but some may be present on the skin at birth or shortly after. One type, called congenital melanocytic nevi (CMN), are brown or black spots that turn up most commonly on the buttocks, thighs, and trunk, although they can also appear on the scalp and extremities. These spots are often raised and can be as small as a millimetre\ or two or as large as 14 cm across. Over time, CMN may fade or change in thickness and colour or sprout hairs. Those born with CMN may be at increased risk for skin cancer as adults.

    Another type of mole called a slate gray nevi (once referred to as Mongolian blue spots) are flat blue or gray moles that can look like a bruise. Slate gray nevi are more common in Asian or darker-skinned infants, and most fade after a few years.

Vascular birthmarks

Vascular birthmarks are red, pink, or bluish marks that develop on the skin where there are an increased number of blood vessels.

  • Macular stains or nevus simplex
    These are the most common vascular birthmarks and they go by several names - salmon patch, stork bite, or angel kisses. The harmless marks can often be found on the head or neck and may fade or remain until adulthood.

  • Hemangiomas
    About 1 in 10 infants have hemangiomas, which are benign red or pink overgrowths of blood vessel cells. More girls are affected than boys, and the birthmarks are more common among white infants, those born prematurely, and twins. In more serious but rarer instances, hemangiomas occur along with internal lesions on the liver, lungs, or other organs.

    The spongy, raised, red or pink marks most commonly appear on the head and neck, and they can also develop on the trunk, arms, and legs. Hemangiomas can grow quickly to 7.5 cm in size. Most of the marks go away without treatment between the ages of 1 and 5 years, with only a faint mark as a reminder of what was there before.

    Hemangiomas can develop sores that cause pain, bleeding, scarring, or infection. Rarely, and depending on size and location, the marks can impair vision, hearing, or breathing. Fast-growing or problematic hemangiomas may be treated with medications or laser treatments.

  • Port wine stains
    About 1 to 3 in 1,000 babies are born with the birthmarks named for their blushed-wine colours. Port wine stains start out pale pink and turn red or purple as a child gets older. Most port wine stains appear on the face and neck and may develop a bumpy, thick surface.

    Further examination may be advised for infants born with port wine stains to rule out any related conditions. These permanent birthmarks can be quite visible, but they cause a child no itch or physical pain. If bothered by the way a port wine stain looks, laser treatments may be used to reduce the appearance. But if no treatment is recommended, parents should care for the affected skin in the same way they would care for the rest of their infant's skin.

When to see a doctor about a birthmark

Most birthmarks are totally harmless, and many resolve before adulthood. But a birthmark can change, be damaged, or hint at a more serious problem.

Infants born with significant birthmarks will likely be evaluated and the birthmarks will either be treated or closely monitored.

If a birthmark changes in any way you should not hesitate to contact a doctor. Seek medical assistance if a birthmark bleeds; bruises; grows suddenly; changes colour; or becomes firm, painful, itchy, or infected. Treat a bleeding birthmark like any other wound – clean with soap and water, bandage, and apply pressure until bleeding stops. Then contact your doctor.

Your doctor can diagnose and identify birthmarks. If necessary, they will perform additional tests to rule out any medical conditions (e.g., biopsy to detect potential skin cancer).