The evaluation of a perianal abscess begins with a history and physical exam.

Physical findings in someone with a perianal abscess may include:

• Anal tenderness
• Swelling of the skin around the anus
• Redness of the skin around the anus
• Pus draining from the anus

Tests are not necessary to make the diagnosis of perianal abscess.

Tests that may be used to evaluate a perianal abscess include:

• Anoscopy:
• An instrument is used to view the inside of the anus and rectum
• Complete blood count
• Cultures of pus
• CT scan of the pelvis