The first thing to consider is allergic purpura when small red dots appear on the back of the feet, especially in some pediatric patients, such as children. This is because allergic purpura, which mainly occurs in the front of the neck, lower limbs, calves, back of the feet and ankles, is prone to cause this small red spots. There are also some patients, such as wearing sports shoes, which are tighter and lead to compressive purpura, resulting in subcutaneous bleeding, also prone to this small red dots. The actual fact is that you will find a lot of people who are not able to get a good deal on this kind of things.