What are stretch marks?
Stretch marks are fine lines on the body that occur from tissue under your skin tearing from rapid growth or over-stretching. It is a common condition that does not cause any significant medical problems but can be of cosmetic concern for some people. Other names for stretch marks are:
- Stria (single) or striae (plural) — the original meaning for stria was a furrow
- Adolescent striae (stretch marks in adolescents)
- Physiological striae (which are not associated with an underlying disease or condition)
- Pathological striae (which are due to an underlying disease or condition)
- Striae rubrae (which are red)
- Striae albae (white)
- Striae atrophicae (thinned skin)
- Striae gravidarum (following pregnancy)
- Striae distensae (stretched skin)
- Striae nigrae (black)
- Striae caerulea (dark blue).
See also elastotic striae (linear focal elastosis).
Who gets stretch marks?
Stretch marks are very common, affecting 70% of adolescent girls and 40% of boys. They occur in certain areas of the body where the skin is subjected to continuous and progressive stretching. These include:
- Abdomen and breast in pregnant women
- Adolescents undergoing growth spurts (thighs, buttocks, breasts)
- Shoulders in body-builders
- Obese or overweight people
Stretch marks can also occur from prolonged use of oral or topical corticosteroids and from anabolic steroids. They are also a feature of the disease Cushing syndrome, where increased adrenal cortical activity excessive. They are seen more often in people with Marfan syndrome.
What do stretch marks look like?
An early sign of stretch marks developing is when an area of skin becomes flattened and thin with a pink colour. This may also occasionally be itchy. Soon reddish or purplish slightly swollen lines develop perpendicular to the direction of skin tension (striae rubrae). Over time, these lighten to become whitish or flesh-coloured and much less conspicuous (striae albae). Stretch marks are usually several centimetres long and 1–10 mm wide. Those caused by corticosteroid use or Cushing syndrome are often larger and wider and may involve other regions, including the face.
Stretch marks (striae)
The histopathological features of striae rubrae on skin biopsy include:
- Lack of mast cells
- Structural changes in collagen bundles
- Prominent fibroblasts
- Dermal oedema
- Perivascular lymphocytes
- Reduced fibrillin microfibrils.
Striae albae resemble scar tissue:
- Epidermal atrophy
- Loss of skin appendages
- Densely packed collagen bundles parallel to the skin surface.
Striae can be confused with linear focal elastosis, which has increased elastic fibres on histopathology.
What treatment is available for stretch marks?
Stretch marks usually are only a cosmetic problem, but rarely, if extensive they may ulcerate or tear easily in an accident. Stretch marks occurring in adolescents become less visible over time and generally require no treatment. In other cases, if stretch marks are a cause of concern then the following treatments, or others, can be tried, but have not been proven to be effective:
- Topical retinoid therapy
- Chemical peels
- Pulsed dye laser therapy
- Fractional thermolysis
- Skin needling