Stretch marks appear as lines on the skin that start as raised red lines. Turning purple they eventually fade into flat silver streaks. The medical technical name for this type of scar is a stria. When the skin is stretched over a short period of time is when stretch marks occur such as during pregnancy. The skin is made up of three distinct layers, the epidermis (outside layer), the dermis (middle layer), and the subcutaneous (inside layer), where fatty tissue is found. The layer which keeps the skin firm and supported is the dermis. Supplying the skin with nutrients through blood cells and containing nerves to give us feeling are also jobs of the dermis. The dermis is where stretch marks occur.

The skin is able to stretch by the dermis layer as it is made up of strong fibres connected to each other. Eventually these fibres can break as they become thinner and less elastic over time. Stretch marks appear where these fibres break and the skin is thinner. The reddish colour from stretch marks is because they are in areas where the skin is stretched thinly and thus blood vessels show through.

Stretch marks begin as red lines on the skin but depending on the colour of your skin, they may also look pink, reddish brown, or dark brown. The lines then usually change to purple, before gradually flattening out. The lines get flatter and fade usually to a shade lighter than your own skin tone. This process however may take many years.

Stretch marks appear anywhere on the body where the skin has been stretched. However usually more so in places where fat is stored, such as abdomen, breasts, upper arms, thighs and buttocks. People who put on a lot of weight in a short period of time often will notice stretch marks in these places.

Stretch marks aren't harmful and thus there is usually no need to consult your GP about them. However, if a stretch mark is unsightly and they are making you unhappy, it is worth seeing your dermatologist to discuss treatment options. There is no one specific treatment for stretch marks. Majority of stretch marks fade over time and are usually not that noticeable. You may like to try the following treatments however if you are worried about the appearance of your stretch marks or if they cover a large part of your body.

In the early stages, stretch marks can often be helped with over-the-counter moisturising creams, particularly those made with vitamin E or vitamin A. Alpha hydroxyl acids (AHAs) often contained in these products is an ingredient which can help. To date clinical studies have not shown that these sorts of creams can prevent stretch marks, but they may work to improve the look of stretch marks in the short term. These creams also help stretch marks by encouraging circulation through the rubbing in action and by keeping the skin supple.