This site is intended for health professionals only

At the heart of general practice since 1960

Symptom sorter - diagnosing an anal swelling

GPs Dr Keith Hopcroft and Vincent Forte continue their series on how to make sense of common presentations

GPs Dr Keith Hopcroft and Vincent Forte continue their series on how to make sense of common presentations

The GP overview

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 (for example, fistulae, carcinoma).

Differential diagnosis


• Prolapsed pile

• Perianal haematoma

• Skin tags

• Perianal abscess

• Rectal prolapse


• Warts

• Sebaceous cyst

• Sentinel pile

• Infected pilonidal sinus


• Hidradenitis

• Anal fistula

• Carcinoma

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 STD – and possible carcinoma.

If needed, 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. Unusually for primary care, it's the examination, rather than the history, that usually provides the definitive diagnosis.

• If there is a discharge as well as a lump, 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 requires urgent surgical attention.

• A persistent, ulcerating anal swelling, especially in the middle aged or elderly, requires urgent biopsy to exclude carcinoma.

Dr Keith Hopcroft is a GP in Basildon, Essex

Dr Vincent Forte is a GP in Gorleston, Norfolk

This is an extract from the third edition of Symptom Sorter, published by Radcliffe Publishing ISBN-10 1 84619 195 5.

Anal swelling

Rate this article 

Click to rate

  • 1 star out of 5
  • 2 stars out of 5
  • 3 stars out of 5
  • 4 stars out of 5
  • 5 stars out of 5

0 out of 5 stars

Have your say