76 Year Old Female. 4'9". Weights 74-78. Has Had Throat

76 year old female. 4'9". weights 74-78. Has had throat cancer, cleared. Has had hysterectomy 5 years ago. Done with robot in attendance. About every six weeks, her belly button gets inflamed, bloody, hurts. She has IBS, rumatoid (spelling sorry) arthritis, very bad spine. In the past she was very enemic, but she's been taking Boost with high protein the last 5-6 months and the last test shows she's not enemic. The doctor takes blood samples, gives her antibiotics. And six weeks later, it happens again. She's really concerned about this. What do you think it could be?