An anal abscess is a collection of pus that develops in the tissues around the anus.
An anal abscess occurs when bacteria lodge in the small glands that are normally present between the inner and outer layers of the anal sphincter muscle. The collection of bacteria causes inflammation and infection of the glands, resulting in an abscess. This may extend to various areas around the anal canal to involve the anal sphincter muscle and surrounding structures. The abscess may enlarge and burst through the overlying skin or may be drained by means of a surgical procedure.
Symptomatically, the abscess presents as constant throbbing pain due to the increased pressure in the area of the abscess. Other symptoms may include fever and sweating.
To treat the abscess the pus needs to be drained by making an opening in the overlying skin. This may be done under local anaesthetic or a larger abscess may require drainage under general anaesthetic. Antibiotics may be used to control the infection but drainage of the pus is the only way to remove the collection.