The most common cause of anal swelling is rectal inflammation or sinus inflammation, and if there are hemorrhoids or anal fissures, it is also possible to have anal swelling. The most important thing is to rule out the possibility of prostatitis, which can also lead to anal swelling during the onset of prostatitis, and to rule out the possibility of pelvic inflammation in women, which can also easily lead to anal swelling. It is also important to rule out that during the menstrual period, the pelvic congestion can easily lead to anal swelling.