Practice Essentials
Striae distensae, a common skin condition, do not cause any significant medical problem; however, striae can be of significant distress to those affected. Commonly called stretch marks, they represent linear dermal scars accompanied by epidermal atrophy. Striae distensae are usually a cosmetic problem; however, if extensive, they may tear and ulcerate when an accident or excessive stretching occurs.
(See the image below.)
Striae distensae in pregnancy. Baby is due in less than 2 weeks. Courtesy of Patrick Fitzgerald and Wikimedia Commons.
Approximately 90% of pregnant women, 70% of adolescent females, and 40% of adolescent males (many of whom participate in sports) have stretch marks. Striae affect adolescents, pregnant women (striae gravidarum), and patients with excessive adrenal cortical activity. Stretch marks affect persons of all races and women more commonly than men. Adolescents with striae can expect their striae to be less visible with time.
In a comparison study using 150 striae sites in 19 patients, Lin et al found polarization-sensitive optical coherence tomography (PS-OCT) to be useful for assessing striae severity when compared to visible light dermoscopy. They hypothesize this usefulness is due to the ability of PS-OCT to measure the local subsurface birefringence in tissue. [1]
Treatment with tretinoin, flashlamp pulsed dye laser, and chemical peels significantly improves the clinical appearance of early, active stretch marks.
Pathophysiology
Striae distensae affect skin that is subjected to continuous and progressive stretching; increased stress is placed on the connective tissue due to increased size of the various parts of the body. It occurs on the abdomen and the breasts of pregnant women, on the shoulders of body builders, in adolescents undergoing their growth spurt, and in individuals who are overweight.
Factors leading to the development of striae have not been fully elucidated. Striae distensae are a reflection of "breaks" in the connective tissue. Skin distention may lead to excessive mast cell degranulation with subsequent damage of collagen and elastin. [2] Prolonged use of oral or topical corticosteroids or Cushing syndrome (increased adrenal cortical activity) leads to the development of striae. Genetic factors could certainly play a role, although this is not fully understood.
In a letter to the editor of the Journal of Investigative Dermatology, Tung et al conducted genome-wide association analysis and found evidence that implicates elastic microfibrils in the development of nonsyndromic striae distensae. [3]
Oakley and Patel expound on the pathophysiology of stretch marks, asserting that origination of striae is thought to involve release of elastase due to mast cell and macrophage activity. As a result, the mid-dermis undergoes elastolysis, followed by collagen and fibrillin reorganization. [4]
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Striae distensae on the torso of a 13-year-old boy. One-day duration. Courtesy of Wikimedia Commons.
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Female torso with striae distensae from pregnancy. Courtesy of Parenting Patch and Wikimedia Commons.
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Striae distensae in pregnancy. Baby is due in less than 2 weeks. Courtesy of Patrick Fitzgerald and Wikimedia Commons.
