It might help. I've never tried it. Enemas in general are very helpful, especially coffee enemas. The reason the garlic clove insert works well is because it stays there all day or until you poop it out. It's a road block for the critters and kills candida working its way down the colon. The enema is washed out more quickly in comparison, so you may not have extended relief. I've also read some people get great results from adding a few drops of lavender essential oil to a saline enema and I've also read that garlic enemas can really upset your gut flora balance because it has antibacterial properties. Another post I read here once stated that garlic is a neurotoxin and should not be used in enemas because it's too harsh on the body when administered that way.
Bottom line, it's up to you, but my advice would be if you want to try an enema, do a coffee enema and after you're done with that insert the garlic clove.
I hate the term 'pruritus ani' and I'd like people to be aware it's just a fancy phrase for idiopathic anal itch. When a dr gives you this diagnoses, you should know that it just means they have no idea why you are itching. It's used to obfuscate and placate the patient. Many people are satisfied and relieved when their symptom is given a fancy name, despite lack of adequate treatment ("here, use this cream!"). Most doctors will add that it's due to allergies, but they will not investigate further. It's a bullshit "diagnoses". My personal opinion is that all chronic anal itching should automatically be treated as a parasite and candida infection. If you treat for those and get some relief, then you know that's what you're dealing with. If you get zero relief from the protocol I mentioned then you may have something else. Maybe a liver issue? I don't know... All I do know is that no dr will first assume parasites when presented with extreme anal itch, but it should be their first automatic assumption.