Red streaks on the back of the calf may be caused by physiological factors such as prolonged standing, or it may be caused by obesity lines, contact dermatitis, artificial urticaria, etc. 1. Physiological factors: due to prolonged standing will lead to poor blood circulation, causing an increase in the pressure of small blood vessels, resulting in the formation of red blood, fair-skinned people are more obvious. Patients thus have the performance of red stripes behind the right calf. 2. Obesity lines: mostly due to excessive accumulation of subcutaneous fat, or the skin growth rate can not keep up with the speed of the increase in body size and produce. The skin will appear red and white alternating distribution of cord-like texture, which is manifested in the back of the calf with red stripes. 3. Contact dermatitis: due to the contact of the calves with the allergic substances in the form of stripes, erythema, edema, papules and other phenomena, the patient will have the symptom of red streaks on the back of the calves. 4. Artificial urticaria: it often occurs in allergic individuals, and red elevated streaks will appear after artificial scratching, which can subside soon. In addition, linear moss, linear lichen planus, scleroderma, etc. will also appear red streaks. There are many causes of red streaks on the back of the calf, and patients are advised to go to the hospital in time to clarify the cause.