Anorectal Pain

Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

Rare Diagnoses

  • Anal Tuberculosis
  • Cauda Equina Syndrome
  • Endometriosis
  • Trauma
  • Presacral Tumours

Ready Reckoner

Key distinguishing features of the most common diagnoses

Anal FissureHaematomaAbscessPFMalignancy
Began While DefecatingYes No NoPossible No
Visible Anal Swelling NoYesPossible NoPossible
Pain IntermittentPossible No NoYes No
Rectal BleedingYesPossiblePossible NoYes
PR Exam ExcruciatingYesYesYesPossiblePossible

Possible Investigations

Likely:None

Possible:FBC, ESR/CRP, proctoscopy, faecal calprotectin

Small Print:Urinalysis, ultrasound, hospital-based lower GI investigations

  • FBC/ESR/CRP: WCC may be raised in abscess and Crohn’s disease. ESR/CRP raised in these and carcinoma.
  • Proctoscopy valuable if pain allows (specialist might also take biopsy).
  • Faecal calprotectin: May help in diagnosing Crohn’s disease.
  • Urinalysis: Pus cells and blood may be present in prostatitis or invasive bladder tumour
  • Ultrasound of pelvis if pelvic examination reveals a mass. In obscure cases, hospital-based lower GI investigations may be needed.

Top Tips

  • If the patient uses dramatic language (e.g. red-hot poker) to describe fleeting pain, is otherwise well and there are no obvious abnormalities on examination, the diagnosis is likely to be proctalgia fugax.
  • Examine the patient – the cause is usually a thrombosed pile/perianal haematoma, anal fissure or an abscess, and these can usually be diagnosed by simple inspection
  • Provide symptomatic relief but remember to deal with any underlying causes – especially constipation.
  • Don’t forget to ask about thirst and urinary frequency – recurrent abscesses may be the first presentation of diabetes.

Red Flags

  • Preceding weight loss and/or change in bowel habit should prompt a full urgent assessment with carcinoma and inflammatory bowel disease in mind.
  • Some perianal abscesses do not result in external swelling. If PR exam is prohibitively painful, consider this possibility – especially if the patient is febrile
  • In florid or recurrent perianal problems, think of Crohn’s disease as a possible cause.
  • Remember rarer causes in intractable, constant pain in a patient with no obvious signs on PR.

Published: 1st August 2022 Updated: 10th April 2024

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Based on the best-selling book Symptom Sorter. Pulse Reference is designed to help GPs make sense of patient presentations. It analyses a multitude of symptoms commonly seen in primary care and for each presents differentials, distinguishing features, possible investigations and key points. It also provides guides on managing more than 350 conditions. The perspective is very much grass roots primary care, informed by the latest evidence and guidance.

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Disclaimer

Pulse Reference is based on the best-selling book Symptom Sorter. The experts behind Pulse Reference are Dr Keith Hopcroft who is the co-author of Symptom Sorter, a GP in Essex and Pulse’s editorial advisor and Dr Poppy Freeman, a GP in Camden and also a clinical advisor to Pulse. This website is for clinical guidance only and cannot give definitive diagnostic information. Practitioners should work within the limits of their individual professional practice, seek guidance when necessary and refer appropriately.