Management of pharyngeal diphtheria

Pharyngeal diphtheria presents as gross membranous pharyngitis, with or without airway obstruction. Patients with airway obstruction require urgent escorted transfer to hospital, intensive monitoring, and early referral to an otolaryngologist. In patients without airway obstruction, exclude Epstein–Barr virus (EBV) infection because this is a more common cause of severe sore throat. The diphtheria toxin can cause systemic complications including demyelinating peripheral neuritis and myocarditis; electrocardiogram (ECG) monitoring is recommended.

Report cases of pharyngeal diphtheria to the local public health authority^{1 2}. In collaboration with the public health authority, initiate vaccination and clearance antibiotics for contacts of the index case.

Diphtheria antitoxin is the primary treatment for pharyngeal diphtheria. Access to diphtheria antitoxin can be coordinated through the local public health authority³. The antitoxin should be administered in hospital with expert guidance because it can cause acute allergic reactions. For more information on diphtheria antitoxin and public health management of diphtheria, see the Australian Immunisation Handbook [URL].

In patients with pharyngeal diphtheria, the role of adjunctive antibiotic treatment is to eradicate C. diphtheriae, which prevents further toxin production.

For patients with severe pharyngeal diphtheria (eg high fever, extensive neck swelling, upper airway obstruction), antibiotic therapy with benzylpenicillin and azithromycin is recommended until the results of culture and susceptibility testing are available. Use:

If intravenous azithromycin is not available, seek expert advice; see also Antimicrobial drug shortages.

For patients with severe pharyngeal diphtheria with hypersensitivity to penicillins, use azithromycin alone (see dosage above).

Once the results of culture and susceptibility testing are available, combination therapy is not necessary; change to treatment with benzylpenicillin or azithromycin alone. See below for advice on intravenous to oral switch.

For patients with nonsevere pharyngeal diphtheria (eg afebrile, limited neck swelling, no airway compromise), use:

For patients with nonsevere pharyngeal diphtheria with hypersensitivity to penicillins, use:

Intravenous to oral switch: once the patient improves and can swallow comfortably, switch to oral therapy (see Guidance for intravenous to oral switch for guidance on when to switch to oral therapy). Use:

For oral continuation therapy in patients with hypersensitivity to penicillins, use:

If the patient is not fully vaccinated, give age-appropriate catch-up diphtheria vaccination after recovery—see the Australian Immunisation Handbook [URL].