My 4 yo son has a group of 3-5 petichiae on his leg. should i be concerned?

Petechiae on leg: Petechaie represent small broken blood vessels. If your son is sick and has a fever you certainly need to get medical attention right away as this can be a sign of a serious infection. You also need to look all over his body to see if he has other red spots or bruises that might represent low platelets which also needs immediate medical attention. They can also result from very tight socks!

Petechiae: There would be concern if showers of new and scattered petechiae continue to appear or if there is nose or gum bleeding. These symptoms would suggest a platelet or other hematological disorder or a vasculitis. Observe him carefully and have your pediatrician examine him if there are further petechial findings,but hopefully there will be no further problem.