Striae gravidarum, also known as “stretch marks,” arise during pregnancy in the majority of women. Common locations include the abdomen, breasts, buttocks, and thighs. Although the exact etiology is unknown, mechanical stress on connective tissue due to increased size of the various portions of the body is thought to be important. There are no significant differences between skin markings due to skin stretching (striae distensae) of different etiologies, and they can also occur in the settings of disorders of the endocrine system (Cushing’s syndrome), steroid therapy, and rapid weight fluctuations (adolescents undergoing a growth spurt or bodybuilders).
Clinically striae gravidarum appear as wavy linear bands in the skin with their long axis parallel to the lines of skin tension. They are often characterized by their stage of evolution and are classified as recent or old. Striae are initially raised with a red or purple coloration. Early lesions may be associated with mild burning or itching. Over time they become flat or indented and flesh-colored to white with a fine wrinkled texture. Gradually, some striae may resolve over time and become inconspicuous, particularly in the case of adolescent striae occurring in the setting of growth spurts.
Histopathologic findings (those seen under a microscope) demonstrate that stretch marks are a form of scar. In early lesions, the dermal layer of skin reveals inflammatory cells with fragmentation of the collagen and elastic fibers, critical skin components to maintain structure and resiliency. In later lesions, the epidermis, which is the outermost layer of the skin, shows significant atrophy (thinning of the skin).
Striae distensae are primarily a cosmetic problem; however, if extensive, the disfigurement can be quite distressing. Early therapeutic interventions afford the most superior results, but there is no highly effective treatment for this condition. Medications that are applied directly to the skin (topical retinoids) have been shown to improve the appearance; however, they are contraindicated during pregnancy and lactation. Serial chemical peels and laser therapies have also been shown to improve the clinical appearance of striae distensae.