Although rashes can certainly be caused by viruses, other types of internal problems cause rashes as well.
A bacteria, inhaled and then circluated through the system, or ingested bacteria circulating in the gut or blood or system can cause rashes. Staph and Strep can bause a bright red rash that is hot to the touch. parasites like round worms and blastocysts can cause rashes and eczema type rashes. Fungus can cause skin ailments, most definitely with flaking /cracking/itching/burning of the skin.
If it continues on and on, look deeper. Ii would definitely try to boost his immune system. Fulvic acid is good, echinacea, etc.
Lots of info online.