I've been going through lots of test with my doctor. Ones to see if I had a gluten allergy (negative). I tried avoiding dairy to see if I was lactose intolerant, not change. So those are both ruled out. I've also tried to cleam up my diet (less processed foods, more fresh fruits and veg) which has helped. My doctor said he doesn't think it has anything to do with the HPV based on the tests he's run and the symptoms. I still sometimes feel like it might be parasites, but after months of trying different things and due to my family history of bowel problems and especially IBS, that's what my doctor has decided it probably is. At least for right now. I don't have itching very often and he said that some people just get it from time to time, especially with IBS. He recently gave me Bentyl to take "as needed" for IBS. I haven't tried it yet to see if it helps.
Two possibilities need tobe ruled out in your case and these include hemorrhoids which may sometimes start with itching around the anal area and If you have loose stools with blood and mucus in stools with crampy pain in stomach, it could be due to infection (bacterial/amebic) and you need to have stool microscopy done for confirmation. You may also need a colonoscppy and biopsy.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.