an anal abscess is a painful condition in which a collection of pus develops near the anus. Most anal abscesses are a result of infection from small anal glands. When the glands fill with pus, they may burst inward, releasing their infected contents into the spaces around the rectum and anus. This pus causes an abscess, or pus collection, in the spaces surrounding the rectum or anus. A blocked anal gland, a sexually transmitted infection (sti), or an infected anal fissure can cause anal abscesses. Some other risk factors include crohns disease or ulcerative colitis, which. Anal herpes anal sex may spread the herpes viruses hsv-1 and hsv-2. Symptoms include painful sores around the anus that come and go. Up to 50 of the time after an abscess has been drained, a tunnel (fistula) may persist, connecting the infected anal gland to the external skin. This typically will involve some type of drainage from the external opening. When a gland in the anus becomes clogged and then infected, it can produce an anal abscess. This is technically defined as a collection of pus around inflamed tissue. Blocked anal gland rockandroll hi there, i have a small lump on the outside of my anus, i have been to the doctors who have advised me that it is a blocked anal gland and that it should go on its own - i still feel a little uneasy about this and cannot find anything on the web with regard to this (mostly seems to be prevalent in dogs!). characterized by swollen, red swelling on either side of a dogs anus, anal gland infection is caused by bacteria that enters the gland, most likely through the duct. Affected dogs may bite or lick the area beneath their tail, or scoot their bottoms on the ground to alleviate discomfort. Impacted anal glands can quickly become infected and even create an abscess that will push through the skin. When this occurs, it can become incredibly dangerous for your dog. What do anal glands do? Anal glands serve two primary purposes.