Hi
Welcome to the MedHelp forum!
Yes, bruising should worry you. Normally a one year old crawls around a lot, plays on tummy and back and bumps into things. However, this does not cause bruising. A little darkness can be expected around knees due to dirt and frictional rub but that’s all. Bruising could be due to clotting disorders, low platelet count, fragile spider veins, deep vein thrombus, deficiency of Vitamin B12, folic acid, or Vit K, a liver disease or certain cancers. It could also be due to pressure urticaria.
Please consult your child’s pediatrician for primary examination followed by proper investigations. Take care!