My son has a very bad rash/eczema on his buttocks. It has now spread to his entire body. I took him to a doctor yesterday and he says it might be bedbugs but I'm not convinced. We wash our linen twice a week. I'm worried that it might be a children's sickness but he is not ill. No fever. The rash on his buttocks are now sores. He is using antibiotics and cortizone cream at the moment.