your child cannot be adequately diagnosed without an examination. a medical professional will need to see him first-hand; a description is just not sufficient to make this important call. there are literally hundreds of "bumps" that can occur on human skin.
my 5 year old has lots of bumps that itch all over his feet up to his knees. they itch and hurt not red when they fist appear but after he scratches they turn into sores. they are in patchy spots all over his legs and feet.