My Mom Started Getting Sore, Red Bumps On Her Palms

My mom started getting sore, red bumps on her palms and fingertips. The doctor told her that she had a RX for too many pills for a UYI she was treating and took her off of that antibiotic and prescribed a steroid medicine that worked and made her feel really good! Then after that RX was gone the bumps came back, so it must not have been the antibiotic. Please help us figure out what the bumps are caused by.