Absolute:

• Imperforate Anus
• Unwilling patient
• Immunosuppressed patient
• Absence of anus following surgical excision
• Stricture
• Moderate to severe anal pain
• Prolapsed thrombosed internal hemorroids

Relative:

• Severe rectal pain may preclude an awake anoscopy and require sedation
• Recent acute myocardial infarction
• Acute abdomen
• Patients with valvular heart disease or prosthetic valves require prophylactic antibiotics before the procedure
• Patients with coagulopathy (or anticoagulation medication) if biopsy is to be considered
• Major rectal trauma
• Post-operative status (anal surgery)