Stretch marks

Striae, or stretch marks, are a common complaint and can be distressing. They may affect the abdomen, buttocks, thighs, breasts, back, axillae and groin. They are classified according to appearance or epidemiology, as:

striae atrophicans (thinned skin)
striae gravidarum (following pregnancy)
striae distensae (stretched skin)
striae rubrae (red), striae albae (white)
striae nigra (black)
striae caerulea (dark blue).

Striae are difficult to treat effectively.

Striae are a form of dermal scarring associated with stretching of the dermis. They often result from a rapid change in weight (gain and loss) or are associated with endogenous or exogenous corticosteroids. Proposed mechanisms relate to hormones, physical stretch, and structural alterations of dermal collagen and elastic tissue. Adrenocorticotropic hormones promote fibroblast activity and increase protein catabolism. Pregnancy-related hormones may also contribute. Serum relaxin has been described to be lower in women with striae distensae. Deficiency of fibrillin has also been proposed. Genetic factors are unexplored, except that decreased expression of collagen and fibronectin genes is reported to be associated with striae.

Striae distensae occur in pregnancy (43% to 88%), puberty (6% to 86%) and obesity (43%).

Striae atrophicans follow medical conditions, particularly Cushing syndrome/disease, and treatments, usually exogenous topical or systemic corticosteroids, or surgery.

Other associated diseases are Marfan syndrome, anorexia nervosa, various febrile illnesses, and chronic liver disease.

Medications associated with striae also include chemotherapy, prolonged antibiotic therapy, contraceptives, and neuroleptics.

Striae are more common in females than in males and may be more common in certain races. They can appear more prominent in dark-skinned individuals. A positive family history is a risk factor for striae. During pregnancy, striae are more common in younger women than in older women. Several studies have noted greater prevalence with large abdominal circumference and large weight gain (due to fetal size or polyhydramnios).One study reported that striae were more prevalent in smokers than non-smokers.