Red streaks on the skin are a characteristic sign of an infection of the skin or subcutaneous tissues, especially when the infection is spreading from its original site. In this case, other symptoms, such as pain, tenderness, swelling, and warmth typically accompany the red streaks. Red streaks can also be a sign of injury, such as a scratch injury. Striae, sometimes referred to as stretch marks, are streaks of reddened, thin skin that can occur as a result of rapid weight gain or abdominal enlargement during pregnancy. They can also occur in the setting of certain chronic disorders of the connective tissue. An excess of cortisol (Cushing syndrome) can also cause striae.