An urgent warning has been issued by doctors to get immediate help if you have a red line your skin. The appearance of the mark could be a sign of a health emergency. US medic Dr Joe Whittington says the red-coloured streak could be a dangerous infection. He was responding to a video on social media platform TikTok . It showed a red line going from the toes up the leg. He said this could be a symptom of lymphangitis. The infection, he said, can lead to the formation of abscesses or even