Chachi had red bumps that expanded all over his body like you describe. First the vet thought it was an allergic reaction to fleas. He found one dying flea on him when he examined him. When we treated him and it was getting worse not better they did a skin test and found he had mites which is mange. He had to be dipped 6 times every ten days but it has cleared up. He had it all over his back and on his neck and lost all his hair in that area. I think it is mange and like Stewiesmom said it just not showing up. What you described is exactly what Chachi went through. Good luck I hope you get some answers |