Stretchmarks are kinds of little fissures similar to soft scars formed on the skin, due to reduced skin thickness following localised reduced collagen and elastin production by the fibroblasts, the ‘skin making’ cells.
They appear when the skin is subject to exaggerated distension ( extension then loss of volume ).
They are very common, and can be seen among 50% of younger people; 25% of girls and 10% of boys have stretchmarks at puberty, and 50-75% of pregnant women develop them.
Histologically, recent stretchmarks show an inflammatory infiltration, whilst older stretchmarks display a break in the dermal collagen, neocollagenesis and thickening of the elastic fibres.
Stretchmarks appear during puberty, pregnancy, periods of obersity, and after taking certain medicines.