A haematoma under the skin around the anus.
(external haemorrhoid) a painful swelling composed of blood that lies next to the anus. Typically it develops following an episode of straining during defecation or protracted coughing. Perianal haematomas are caused by the rupture of a small vein in the anus. They often heal spontaneously but occasionally rupture. Rarely this is followed by abscess formation. If severe pain continues, surgical removal may be undertaken. See also haemorrhoids.
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