Anal Swelling

Because of embarrassment on the part of the patient, this may well present as a ‘while I’m here’ symptom. The temptation to make a diagnosis without examination should be resisted – some of the causes (such as perianal abscesses) require urgent attention and others may, rarely, provide something of a surprise (e.g. fistulae, carcinoma).

Published: 1st August 2022 | Updated: 15th August 2022

Differential diagnosis

Common Diagnoses

  • Prolapsed Pile
  • Perianal Haematoma
  • Skin Tags
  • Perianal Abscess
  • Rectal Prolapse

Occasional Diagnoses

  • Warts
  • Sebaceous Cyst
  • Sentinel Pile
  • Infected Pilonidal Sinus

Rare Diagnoses

  • Hidradenitis
  • Anal Fistula
  • Carcinoma

Ready reckoner

Key distinguishing features of the most common diagnoses

Prolapsed PilePerianal HaematomaSkin TagsPerianal AbscessRectal Prolapse
Painful PossibleYes NoYes No
Intermittent Possible No No No Possible
Constipated Possible Possible No Possible Possible
Long History Possible NoYes No Possible
Rectal Bleeding Possible Possible No Possible No

Possible investigations

  • In most cases, investigation will be unnecessary. The only exceptions are warts (in which case referral to the local GUM clinic may be required to screen for sexually transmitted disease) and possible carcinoma (in which case biopsy will be performed in secondary care). Also, any suspicion of Crohn’s disease causing perianal disease would be investigated in hospital in the usual way.

Top Tips

  • This is one of those situations in which a brief history can be taken while the patient is undressing, or during the examination. Atypically for primary care, it’s the examination, rather than the history, which usually provides the definitive diagnosis.
  • If a discharge, as well as a lump, is mentioned by the patient, then abscesses, warts, prolapses and fistulae top the list of differentials.
  • The patient with an anal swelling who has obvious difficulty walking into the consulting room has either an abscess, a large perianal haematoma or strangulated prolapsed piles.

Red Flags

  • Recurrent or multiple fistulae suggest Crohn’s disease.
  • If a prolapsed pile is very swollen and painful, it is probably strangulated, and so requires urgent surgical attention.
  • A persistent, ulcerating anal swelling, especially in the middle-aged or elderly, requires urgent biopsy to exclude carcinoma.
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Website 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.