Striae (Rubra and Alba



Striae (Rubra and Alba


Adele Haimovic

Deborah S. Sarnoff



BACKGROUND

Striae distensae (SD), often referred to as stretch marks, are linear atrophic dermal scars covered by an atrophic epidermis.1 They were first described in 1936 by Nardelli as dermal scars caused by skin stretching.2 Although SD do not cause any significant medical problems, they are a common dermatologic condition that is cosmetically concerning and cause significant psychosocial distress in affected individuals. SD are 2.5 times more frequent in women than in men.3 They follow normal skin cleavage lines and are often associated with pregnancy and growth spurts in adolescents. For adolescents the incidence has been reported to be 40% to 70%,1 and for pregnancy the incidence has been as high as 90%.4


PRESENTATION

Patients typically present during puberty, during pregnancy, or after rapid weight changes or muscular changes with a complaint of discolored lines on the abdomen, shoulders, buttocks, or thighs.




PATHOGENESIS

The exact etiology of SD is unclear. Multiple theories, including mechanical stretching, endocrine abnormalities, and connective tissue defects, have been proposed. Genetic predisposition, including family and personal history, as well as ethnicity, appear to play an important role.11

SD often occur after rapid weight gain or increase in height during adolescence or pregnancy. SG affect up to 90% of women in the second or third trimester.4 One common theory is that SD are due to mechanical stretching of the skin and damage of the dermal connective tissue during this rapid growth phase.8 However, studies have contradicted this theory as increased abdominal girth, baseline body mass index, and infant birthweight do not consistently correlate with the development of SG.11,12,13

Hormonal changes may be a key player in the development of SD. Increased glucocorticoid production, as seen with puberty, pregnancy, exogenous steroid use, and Cushing syndrome, is associated with SD. Elevated levels of steroid hormones and their metabolites have been shown in the serum of individuals with striae.14 Adrenocorticotrophic hormone and cortisol are thought to stimulate fibroblast activity leading to alterations of collagen and elastin fibers.5 Cordeiro et al described a significant increase in estrogen and androgen receptors in SD skin compared with healthy skin.14

Genetic factors have been suggested to be important in the development of striae. A familial form of SD,15 as well as SD in monozygotic twins, has been reported.16 Connective tissue diseases, such as Marfan syndrome, are associated with SD.17 Marfan syndrome is associated with a mutation in the gene that is essential for normal elastic fibers, fibrillin. Fragmented elastic fibers may explain the high frequency of SD in individuals with Marfan syndrome.17

Jun 29, 2020 | Posted by in Dermatology | Comments Off on Striae (Rubra and Alba
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