Suggest Treatment For Chest Congestion And Rashes

Hi my 10 yr old has had a cough (chesty, phlegm, etc) for a little over a week. This morning presented with an itchy rash from his knees downwards, and back of legs and hands very hot and red. Took to Dr who diagnosed viral condition and to see. Tonight still coughing periodically and when does so it is continuous for a while, but is now presenting with hives all over his body - am presuming this is part of a "virus" - Dr checked over and said that his chest, etc was clear but had glands up all over his neck.