Rapidly spreading submandibular infection in a penicillin-allergic patient

This is a hospital problem, and the decision rests on airway risk rather than on the size of the swelling alone.

Findings that drive the judgement

• Raised floor of mouth with submandibular swelling indicates infection in the sublingual and submandibular spaces, the anatomical territory that produces Ludwig's angina.
• Muffled ('hot potato') voice, dysphagia and trismus of 20 mm are the classic warning triad for pharyngeal and floor-of-mouth oedema encroaching on the airway.
• Systemic response: temperature 38.6 °C with pulse 112 and respiratory rate 22 show a systemic inflammatory response; saturation of 97% is reassuring now but can fall quickly and is not a reason to relax.
• Rate of change: doubling within 12 hours is rapid progression and predicts further deterioration overnight.

What this means practically Source control - drainage and removal of 37 - cannot be achieved in a clinic with no surgical cover, no anaesthetist and no airway backup. Oral antibiotics as an outpatient would not penetrate an established collection adequately and would delay definitive treatment. This patient needs admission for intravenous antibiotics, assessment by oral and maxillofacial surgery, and probable incision and drainage under general anaesthesia. My job is immediate safe transfer with a clear, spoken and written referral, not definitive treatment.

First, treat the refusal as a communication problem before a legal one. He has capacity, so I cannot compel him, but I can make sure any decision is informed. I would sit him down, switch off the chair, and say plainly: the swelling is in the space around his throat, it has doubled in twelve hours, and the reason I am not treating him here is that the airway can close quickly and a dental clinic cannot open it. I would use concrete, non-technical language and avoid threats.

Practical steps

• Repeat and record baseline observations, including a repeat respiratory rate and saturation, and document the trismus measurement.
• Telephone the maxillofacial team or emergency department while he is in the room, so he hears the plan being made and the receiving team is expecting him.
• Explain that he must not drive himself: he is febrile, tachycardic, has not eaten since morning, and could deteriorate at the wheel. Arrange an ambulance or a responsible adult.
• Keep him nil by mouth in case he needs a general anaesthetic.
• Ask a colleague or the most senior clinician available to speak with him; a second voice often helps.
• If he still refuses, document capacity assessment, the risks explained, the advice given, and that he declined; give written safety advice with an emergency number and advise immediate attendance if he develops drooling, difficulty breathing, neck stiffness or inability to swallow his own saliva. Send a copy of the record to his GP and inform the receiving unit of the refusal.
• Do not send him away with a prescription and no follow-up.

The allergy history matters more than the label A childhood rash after amoxicillin is most likely a benign delayed maculopapular reaction, but I cannot confirm that in an emergency and must not give a penicillin. I would record the exact description, timing and any features of anaphylaxis, and flag it for the receiving team, who can consider allergy testing later. Penicillin is avoided; there is no role for a cephalosporin challenge in a clinic at 8 pm.

Antibiotic choice The purpose is to slow progression during a 45-minute transfer, not to treat definitively. Reasonable options in a penicillin-allergic adult with a severe spreading odontogenic infection include:

• Clindamycin (for example 600 mg intravenously or orally), which covers oral streptococci and most anaerobes, though it carries a Clostridioides difficile risk and is losing favour for prolonged courses.
• Metronidazole plus a non-penicillin beta-lactam or a macrolide where local guidance supports it; metronidazole alone covers anaerobes but not streptococci. I would follow the local formulary rather than invent a regimen, give a single dose, and state clearly in the referral what was given and when, so the receiving team is not duplicating or conflicting.

Analgesia and other measures

• Paracetamol 1 g, with the dose and time documented.
• Avoid intramuscular injections in a patient who may need urgent surgery.
• No NSAID if there is any question of dehydration or renal compromise from poor oral intake.
• Chlorhexidine mouthwash is of no value here.
• Recheck and record observations immediately before departure, and hand over the numbers verbally as well as in writing.