Background: Physiologic striae atrophicae of adolescence presents as transverse red or purple, horizontal, linear streaks, most commonly in the lumbar area. It typically occurs in nonobese adolescents undergoing rapid linear growth and coincides with markers of puberty. However, there has yet to be an exact identifiable cause. Similar to striae distensae and linear focal elastosis, it is now believed mechanical shearing and stretching of the skin do not alone cause striae, but hormonal, diet, lifestyle, and genetic factors may also play a role. Case presentation: A 15-year-old male presented with multiple horizontal linear striae on the lower back. Additionally, a soft, cystic, hyperpigmented plaque was present at the midline of one of the linear plaques. The patient endorsed a recent growth spurt coinciding with the development of the linear striae. Dermoscopy of a linear plaque revealed linear vessels with a faint red-to-violaceous background. Reflectance confocal microscopy of a linear plaque revealed parallel collagen bundles in the dermis and distortion of dermal papillae consistent with striae. Conclusion: Physiologic striae atrophicae of adolescence has been found to occur with rapid linear growth. However, it is likely that hormonal, diet, lifestyle, and genetic factors also contribute to its pathogenesis. Family history of striae, diet, exercise, anaSbolic steroid use, and geographic location are some of the factors that have been linked to this condition. To better understand this condition, a thorough history and physical exam should be performed to identify other possible contributing factors.