Striae (syn. stretch marks)

Striae (stretch marks) are common linear scars that develop in areas of dermal damage produced by stretching of the skin, often during growth or pregnancy.

This chapter is set out as follows:

• Striae usually result from continuous and progressive stretching of the skin, such as in pregnancy, adolescence, obesity and body builders 

• Striae may also result from the prolonged use of topical or oral corticosteroids

• Rarely, striae can result from an underlying condition:
• Cushing's syndrome (obesity with distribution around the abdomen and trunk causing a 'buffalo hump' between the shoulders, and the face leading to the development of a 'moon face' / thin skin with easy bruising / acne and hirsutism in women / hypertension / proximal myopathy / diabetes) 
• Marfan syndrome (disproportionately tall / long and slender limbs, fingers, and toes / lens dislocation / aortic dilatation)

• The factors that lead to the development of striae are poorly understood

• Early lesions may be mildly itchy

Distribution - most common sites

• Pregnancy - abdomen and breasts 
• Adolescents - lumbosacral region in boys, and the thighs, buttocks and breasts in girls 
• Obesity - outer aspects of the thighs
• Body-builders - shoulders 
• Topical corticosteroids - can vary, although are particularly common in the flexures

Morphology

• Early lesions may be raised and irritable, but they soon become flat, smooth and livid red or bluish in colour. Their surface may be finely wrinkled
• Striae are usually several centimetres long and up to one cm in diameter, often irregularly shaped, and have their long axis parallel to the lines of skin tension 
• Over several years the lesions become white or skin-coloured and much less conspicuous
• Systemic corticosteroids, including those with Cushing's syndrome - lesions are often larger and wider, with a more intense colour, and may involve other sites, including the face

• In most patients investigations are not required

• If Cushing's syndrome is suspected - discuss relevant investigations with local pathology / endocrinology department

• The appearance of striae improves over time

• Although many treatments have been used to try and improve the appearance of striae, there is no evidence that any are effective