Reasoning GP · Algorithm · 1-page summary
Sore mouth and tongue
For: adults and children with a sore mouth, tongue, ulcers, white or red patches, or burning. Not for: dental treatment (own dentist, or NHS 111 for urgent dental care) or ulcers during anticancer treatment (acute oncology pathway, UKONS).
Core rule: examine the whole mouth (lift the tongue, palpate the floor of the mouth) and the neck. An unexplained oral ulcer over 3 weeks or a persistent neck lump → NICE NG12 says consider a suspected cancer pathway referral; local safety policy is to refer by default. Never delay it with a topical steroid.
0Stop — call 999 now — before the full history
- Airway: stridor, respiratory distress, drooling, “hot potato” voice, rapidly progressive dysphagia (epiglottitis) → 999. Keep upright and calm, no tongue depressor, never leave alone.
- Ludwig's angina: spreading floor-of-mouth and neck swelling, trismus, “woody” submandibular space, with airway or breathing symptoms → 999
- SJS/TEN: painful erosions with blistering or skin peeling, target lesions, fever, eye or genital involvement → emergency transfer, 999 if extensive or unwell. Stop the suspected drug now; no topical oral steroid.
- Suspected quinsy → Same-day ENT; 999 if stridor or airway compromise.
1Triage by lesion — the 3-week rule (NG12)
| Finding | Action |
|---|---|
| Ulcer >3 wk | Unexplained, or persistent neck lump: NG12 “consider”; local default → Suspected cancer pathway |
| Red patch, lump | Red or red-white patch, lip or mouth lump: consider → Dentist / oral surgery ≤2 wk. Do not wait for pain or bleeding. |
| Fixed white patch | Leukoplakia, changing lichen planus, loose teeth → Urgent dental / oral surgery |
| <3 wk, explained | Treat the cause, document; return if not healed by 3 weeks. |
2Screen — one row is enough
- Deep infection, can't drink, dehydrated (often primary herpes), or immunocompromised with fast-spreading disease → Same-day hospital / OMFS
- Ulcers on chemotherapy or radiotherapy: think neutropenia → Acute oncology pathway
- MRONJ: exposed bone or non-healing socket on bisphosphonate or denosumab → Urgent dental / OMFS. Do not stop the drug.
- Behçet's: recurrent oral and genital ulcers, eye, skin or vascular features → Urgent specialist
- Fixed white plaques with immunosuppression or weight loss → offer an HIV test; oral medicine or sexual health.
- Awaiting cancer clinic and it bleeds, grows or nodes appear → Same-day call to the team
3Assess — good light, gloves, whole mouth
☐ Lips, buccal, gums, palate, oropharynx ☐ Lateral and ventral tongue, floor of mouth (bimanual) ☐ Neck nodes ☐ Drugs: NSAIDs, nicorandil, methotrexate, antiresorptives, inhaled steroid, antibiotics
Targeted tests only: FBC, ferritin, B12, folate; coeliac serology; HbA1c; HIV test. Not for a typical single minor aphthous ulcer. No broad autoimmune panels or swabs for a first thrush episode.
4Classify — only once blocks 0–2 are clear
- Aphthous — shallow, grey base, red halo; minor 1–5 mm, heals in 1–2 weeks.
- Candida — plaques wipe off to a red base; inhaled steroid, antibiotics, dentures, diabetes.
- Lichen planus — white lacy striae, both cheeks → dental / oral medicine surveillance.
- Geographic tongue — migrating red patches, pale borders; benign.
- Burning mouth — normal mucosa, peri- or postmenopausal; diagnosis of exclusion.
- Uncertain — persistent ulcer with no benign diagnosis → Urgent dental / oral surgery
5Treat today — doses: NICE/SPC, BNF, local formulary
- Confirmed aphthous: hydrocortisone 2.5 mg buccal tablets, or betamethasone mouthwash (off-label, spit out); benzydamine; SLS-free toothpaste.
- Candida: miconazole oral gel, or nystatin if on warfarin (MHRA). Fluconazole only if extensive, severe or refractory (check pregnancy, interactions). Inhaled steroid: rinse and spit, spacer.
- Herpes: topical aciclovir early; primary gingivostomatitis — consider oral aciclovir if early and severe (BNFC); fluids.
- Burning mouth: exclude causes; psychological therapy. Clonazepam only after oral medicine advice.
6Refer routinely
- Lichen planus; refractory major aphthae; burning mouth needing drugs → oral medicine.
- Deficiency found → treat and recheck at 3 months.
- Dentures: out at night, cleaned daily, dental review. Smoking → NHS Stop Smoking.
7Never reassure by
- A topical steroid trial for an ulcer over 3 weeks.
- A painful, soft or benign-looking lesion: cancer can be all three.
- A non-smoker or non-drinker (HPV-related cancer).
- Looking only at the front of the mouth.
- Treating a white patch that will not wipe off as thrush.
- A red patch that is not painful, swollen or bleeding.
8Safety-net — say it, then document it
999 “Call 999 for difficulty or noisy breathing, drooling or being unable to swallow saliva, or fast-spreading swelling under the tongue or in the neck.” Same day: “Blistering or peeling skin or sore eyes with mouth sores, being unable to eat or drink enough, or a fast-spreading mouth infection — contact us today.” Give a date: “Come back if any ulcer, lump or patch has not healed within 3 weeks.” Track every cancer referral to an outcome.
✓Safe to leave primary care only if — all five, documented
No block 0–2 feature
Whole mouth, floor of mouth and neck examined
Size, site, duration recorded; referral made if >3 weeks
Drugs reviewed (warfarin, antiresorptives, inhaled steroid)
Safety-net given with a 3-week date
Summary of the full Reasoning GP sore mouth and tongue algorithm, which holds the detail, examination, causes and evidence. Sources: NICE NG12 (updated April 2026); BSOM guidance; product SPCs; MHRA; UKONS acute oncology (2023); SDCEP MRONJ (2017). Clinical reference — follow local referral pathways and check doses: NICE/SPC, BNF.