How can I get rid of these itchy red bumps all over my body?

Depends. If those itchy red bumps are red and look like welts, then they are likely hives and should respond to antihistamines such as claritin, (loratadine) allegra, zyrtec or clarinex. Antihistamines can decrease the itching. The next step is to try to identify the reason for the rash. An allergist or dermatologist can be of assistance here.