I too have had 3 rounds of doxil (3 weeks apart). Breast cancer in 2003 that spread to liver 2006. Doxil is my 3rd drug they tried. My doctor said the rash can show up wherever there is friction, like bra and panties. I too have the rash but mine is not as itchy as your moms. They told me the itch is due to dry skin the doxil can also produce blisters when bad. They told me to use bag balm or utter cream to keep the rash area moisturized. If the rash gets bad she will need a break from the doxil!