Dental & Oral Emergencies

This page covers odontogenic (dental) infection — the presentation most likely to reach a GP or urgent-care clinician before a dentist. Dental trauma and dry socket are not yet covered.

Background

Acute odontogenic infections arise from the dental pulp (caries, restoration breakdown, trauma), periodontal tissues (advanced periodontitis) or pericoronal tissues (a partially erupted mandibular third molar). Untreated, infection can progress from a localised abscess to a spreading infection of the face or neck soft tissues.

Rare but serious complications include Ludwig angina — a severe bilateral infection of the submandibular, sublingual and submental spaces with risk of airway compromise — and necrotising soft-tissue infection. Distant spread can cause sepsis or seed the heart valves, bone, brain, neck or mediastinum; patients with profound immune compromise can deteriorate rapidly even from a localised infection.

The key management principle across every category below is the same: a dental procedure to drain pus and remove the source of infection is what treats an odontogenic infection. Antibiotics are an adjunct, not a substitute — reinforce this whenever a patient is started on antibiotics before being seen by a dentist.

Severity

	Localised	Spreading — no severe features	Spreading — severe/systemic features
Facial swelling	No	Yes	Yes, often marked
Systemic features	No	No	Yes — see red flags below
Setting	Community dental	Community dental + oral antibiotics	Hospital — urgent transfer

Red flags for airway compromise — any of: difficulty breathing or swallowing, swelling of the floor of mouth, trismus, neck swelling, significant facial swelling and pain. Swelling of the upper third of the face occluding the eye is a rare sign of cavernous sinus thrombosis.

Systemic/sepsis features — pallor, sweating, tachycardia, temperature above 38°C or below 36°C; signs of sepsis (impaired consciousness, respiratory rate ≥22/min, systolic BP <90 mmHg, poor peripheral perfusion or mottled skin, reduced urine output) mean life-threatening organ dysfunction and need urgent transfer.

If severity is unclear, seek expert advice rather than guessing — the categories form a continuum, not always a clean-cut division.

Differential diagnosis

Before diagnosing an odontogenic infection, consider osteomyelitis of the jaw (unresolved oral infection with systemic features and localised bone pain/tenderness — refer to an oral and maxillofacial surgeon or hospital), medication-related osteonecrosis of the jaw, osteoradionecrosis (prior radiotherapy), and salivary gland infection (submandibular or parotid) — imaging can help differentiate these from a dental source. After dentoalveolar surgery, also consider alveolar osteitis (dry socket) and ordinary postsurgical inflammation before diagnosing infection.

Localised odontogenic infection

Periapical, pericoronal or periodontal abscess with dental pain and tenderness on tapping the tooth, with or without visible localised swelling or pus, and no facial swelling or systemic features.

Management: prompt referral to a dentist for the definitive procedure (root canal treatment, periodontal debridement, tooth extraction, or incision and drainage of a pointing abscess). Offer systemic analgesia. For a pericoronal infection, add saline or chlorhexidine irrigation/rinsing, which may itself resolve a mild case while awaiting dental review.

Antibiotics are not routinely needed if a dental procedure will happen within 24 hours — prompt drainage removes the infection source and any bacteraemia resolves quickly. Start antibiotics (using the spreading-infection-with-delayed-treatment regimen below) only if a procedure is unlikely within 24 hours, if a tooth fragment/root breaks off and its removal is delayed, or in a patient with profound immune compromise (discuss with their specialist first).

Spreading infection without severe features

Facial swelling with dental/facial pain, with or without visible abscess/pus, but none of the airway or systemic red flags above.

Management: dental procedure in the community (drainage, ideally with pus sent for culture before any antibiotic is given — aspirate into a sterile jar; a swab does not adequately preserve anaerobes), plus oral antibiotics.

• Dental procedure achievable within 24 hours — penicillin monotherapy: phenoxymethylpenicillin 500 mg (child 12.5 mg/kg up to 500 mg) orally 6-hourly for 5 days, or amoxicillin 500 mg (child 15 mg/kg up to 500 mg) orally 8-hourly for 5 days. Non-severe penicillin hypersensitivity: cefalexin 500 mg 6-hourly. Severe hypersensitivity: clindamycin 300 mg (child 10 mg/kg up to 300 mg) orally 8-hourly for 5 days.
• Procedure delayed beyond 24 hours — add anaerobic cover: metronidazole 400 mg orally 12-hourly plus either phenoxymethylpenicillin or amoxicillin (doses as above) for 5 days, or amoxicillin+clavulanate 875+125 mg orally 8-hourly as a single drug. Same penicillin-hypersensitivity substitutions as above, with metronidazole continued alongside cefalexin or clindamycin.

Follow-up: review at 48–72 hours once source control (drainage) has been achieved. If improving, the patient can stop antibiotics early — completing the full course is not necessary. If not responding by 48–72 hours, reassess for emerging red flags (urgent transfer if present), confirm source control, and step up the regimen (add metronidazole to penicillin monotherapy, or switch to amoxicillin+clavulanate) with review again in another 48–72 hours. If still not responding, seek expert advice — culture-guided therapy or hospital transfer may be needed.

Spreading infection with severe features

This is a medical emergency.

1. Call an ambulance.
2. Give 100% supplemental oxygen by mask if breathing difficulty or cyanosis.
3. Let the patient adopt a position of comfort.
4. Arrange urgent transfer to a hospital with an oral and maxillofacial surgeon (or anaesthetic/emergency airway facilities if OMFS access is difficult).
5. Contact the receiving service directly to alert them and get pre-hospital advice.

If transfer to hospital is likely to be delayed by an hour or more (a common rural/remote scenario), and staff and facilities allow it, consider starting resuscitation and giving an immediate antibiotic dose before or during transfer — do not delay antibiotics to collect blood cultures in a critically unwell patient. Base pre-hospital antibiotic choice on local sepsis protocols where they exist.

For a patient without signs of sepsis but with severe local features, once in hospital, empirical intravenous therapy is benzylpenicillin 1.8 g 6-hourly plus metronidazole 500 mg 12-hourly (or amoxicillin+clavulanate IV as a single-drug alternative), alongside urgent surgical drainage. Non-severe penicillin hypersensitivity: cefazolin plus metronidazole. Severe hypersensitivity: clindamycin 600 mg IV 8-hourly. Suspected sepsis from an odontogenic source needs expert advice — while awaiting it, the mediastinitis/deep-neck-space sepsis regimen (broader gram-negative and staphylococcal cover) is used because the source and likely pathogens are similar.

Infection after dental surgery

Uncommon, and prophylactic antibiotics do not reduce its incidence. Suspect it with cellulitis around the surgical site, a fluctuant site, purulent discharge, foul taste, or pain/swelling worsening or not improving by day 4 — but first exclude ordinary postsurgical inflammation and alveolar osteitis (dry socket). Severe local or systemic features are managed as above.

Management: regular antiseptic mouthwash, washout/debridement of the socket, drainage and culture of any localised collection if feasible, oral antibiotics (usually needed here because complete drainage of a postoperative site is often not achievable — use the spreading-infection delayed-treatment regimen above unless culture results direct otherwise), removal of any residual root/tooth fragment seen on X-ray, and analgesia.

Why penicillin is preferred

Odontogenic infections are typically polymicrobial — anaerobes (Prevotella, Fusobacterium, Porphyromonas), viridans streptococci, Haemophilus species and staphylococci, with anaerobes the major pathogens in abscesses. Phenoxymethylpenicillin is preferred to amoxicillin as first-line because of its narrower spectrum. Amoxicillin+clavulanate is broader-spectrum and works as an alternative, but is not first-line for antimicrobial stewardship reasons. Metronidazole monotherapy is never adequate alone, since it has no activity against the aerobic component of a mixed infection.

Safety-netting

Every patient started on antibiotics before dental review needs an explicit safety net. Dental treatment is still required as soon as possible, even if symptoms improve on antibiotics.

Tell them to seek urgent review if swelling spreads, breathing or swallowing becomes difficult, or they develop fever or systemic symptoms.