My Wife Had Back Surgery On Oct. 13. She Is

My wife had back surgery on Oct. 13. She is now fighting a rash on her back. Initially we thought it was related to tape adhesive from the steristrips over the incision and/or the tegaderm. Now we are wondering if it is due to a cleaning/antibiotic/surgery prep. product used generally over her back prior to starting the surgery. What products are typically used broadly on the area surrounding the surgery site, and could this have upset the natural flora of her skin sufficiently to cause the rash? Also, what should we use to stop the rash?