What Causes Shortness Of Breath While On Medrol And Diovan?

My 84 yr old father started with a rash in mid September a week after a flu shot. He has seen a dermatologist, internist and his cardiologist. I have also taken him to the ER. The rash is accompanied by swelling in his extremities. 2 rounds of prednisone caused a 14 lb weight gain. Medrol has reduced the swelling but the rash and swelling return after the Medrol pack is finished. He also has shortness of breath. His PCP had him discontinue his meds which were diovan, pravastatin, glipizide and Plavix. He is currently taking a full aspirin daily. Any ideas as to what could be causing the rash and shortness of breath?