Reasoning GP · Algorithm · 1-page summary
Anal and perianal lumps in adults
For: adults with a new anal or perianal lump in primary care. Not for: children (use paediatric pathways); rectal bleeding without a lump (use the rectal bleeding algorithm); anal pain without a lump (use the anal pain algorithm).
Core rule: not every lump is a pile. Inspect at rest and straining, and do a PR. An unexplained anal mass or anal ulceration, or a rectal mass → consider a suspected cancer pathway referral without waiting for FIT. Haemorrhoids do not explain bleeding without assessment.
0Stop — call 999 now
- Fournier's gangrene: perianal or scrotal swelling with crepitus, rapidly spreading redness or skin discolouration, or pain out of proportion to the signs → 999. Diabetes raises the risk.
- Strangulated rectal prolapse: cannot be reduced and looks dusky, black or ischaemic, or is severely painful → 999. Haemodynamic compromise from rectal haemorrhage → 999
- While waiting: do not force reduction of an ischaemic, necrotic or severely painful prolapse; gentle reduction only by trained clinicians. Do not drain an abscess in primary care.
1Triage by what the lump is like
| Lump | Action |
|---|---|
| Tender, fluctuant ± fever | Perianal abscess → Same-day surgical drainage. Antibiotics do not replace drainage. |
| Prolapse, won't reduce | Healthy-looking → Same-day surgical. Dusky, black or very painful → 999 |
| Hard, fixed, ulcerated | Or inguinal nodes → block 2, no FIT |
| Sudden, blue-black, painful | Thrombosed pile: severe, ≤ about 72 h → consider Same-day surgical excision assessment; else conservative |
| Soft, painless | Pile, tag, wart or reducible prolapse → classify (block 4) |
2Screen — NICE NG12 (updated April 2026)
- Unexplained anal mass or anal ulceration → consider an anal-cancer Suspected cancer pathway referral. No FIT first.
- Rectal mass → consider a colorectal Suspected cancer pathway referral. No FIT first.
- Rectal bleeding, weight loss or altered bowel habit, no mass → quantitative FIT per NG12; ≥10 µg Hb/g → colorectal pathway. Blood mixed with stool → Urgent investigation.
- HIV or immunosuppressed: unexplained mass or ulcer → as above; rapidly enlarging warts or proctitis → Same-day GUM/HIV team.
3Assess — consent, chaperone, document
☐ Inspect at rest and on straining (or on a commode): site, size, surface, colour, reducibility ☐ PR (not mandatory in an exquisitely tender abscess) ☐ Inguinal nodes ☐ Proctoscopy if trained ☐ Sexual history → rectal NAAT, syphilis serology, HIV test by risk, not for every lump ☐ Abscess: FBC, CRP, HbA1c
Not in primary care: abscess drainage, biopsy, routine HPV typing. Lidocaine must not delay referral.
4Classify — only if blocks 0–2 are negative
- Haemorrhoids — painless, bright red blood on the paper. Grade by prolapse: II reduces itself, III needs manual reduction, IV irreducible.
- Thrombosed external pile — sudden severe pain, firm blue-black lump at the margin; most settle in 2–3 weeks.
- Skin tag — soft painless flap, benign. Warts — multiple, cauliflower-like.
- Rectal prolapse — fleshy lump with concentric rings on straining.
- Uncertain — persistent lump not clearly benign → colorectal assessment and biopsy.
5Treat today — doses: NICE/SPC, BNF, local formulary
- Piles I–II: fibre gradually, fluids, one laxative by stool consistency; topical steroid ≤ about 5–7 days.
- Thrombosed pile, late or improving: paracetamol, sitz baths, stool softener. NSAID only if no bleeding, anticoagulant, renal, ulcer, heart-failure or frailty risk.
- External warts (if trained): podophyllotoxin 0.15% cream BD × 3 days, 4 days off, or imiquimod 5% 3×/week. Never in the anal canal; avoid podophyllotoxin in pregnancy.
- Reducible prolapse: pelvic floor exercises, stool softeners.
6Refer routinely
- Colorectal: grade III–IV piles; II–III not settling at 6-week review (banding); rectal prolapse; recurrent abscess; post-drainage discharge or non-healing opening (fistula); symptomatic tag.
- GUM: new or uncertain, internal, extensive or recurrent warts; immunosuppression; pregnancy; treatment failure.
- Warts at 4–8 weeks: rapid growth, atypical look or no response → specialist and biopsy, not another cycle.
7Never reassure by
- "It's just a pile" — piles and colorectal cancer coexist.
- A negative or unreturned FIT when concern remains.
- Antibiotics instead of draining an abscess.
- An inspection at rest only — prolapse shows on straining.
- Another topical cycle for warts that fail or look atypical.
- A cream or lidocaine that eases a lesion not yet diagnosed.
8Safety-net — say it, then document it
999 “Call 999 if a lump that has come out turns dark or black or is very painful and will not go back, if the skin around your bottom crackles, goes red very fast or hurts far more than it looks, or if heavy bleeding makes you faint.”
Same day: “If a prolapse will not go back in, you need to be seen by the surgeons today. Contact us the same day for a new swelling after drainage, warts growing quickly if your immunity is low, or new bleeding during treatment.”
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Inspected at rest and straining, PR done or reason recorded
Lump named, or uncertainty → specialist
FIT, STI screen and review date set as indicated
Safety-net given and documented
Summary of the full Reasoning GP anal lumps algorithm, which holds the history, differential, examination and evidence. Sources: NICE NG12 (updated April 2026), NICE HTG690 (formerly DG56), BASHH anogenital warts 2024, SPS/BASHH podophyllotoxin PGD 2024, ESCP anal fistula 2023, ACPGBI, UKHSA Green Book (HPV). Clinical reference — follow local pathways and check doses: NICE/SPC, BNF.