My friend has a skin rash, he said it started out small and just it started to spread. red areas and is itchy. what kind of rashes could it be?

Multiple causes: If could be related to bites/scabies or may have started from something his skin came in contact with. Have your doctor examine it to make the diagnosis and begin proper treatment. All the best

Rash: This can't be diagnosed with the information that is available. A history, physical examination & other studies may be needed to determine cause/causes. Once accurately assessed a treatment plan can be developed.