A nurse with no dental history who has always attended six-month recalls arrives with marked facial swelling and a visible spider bite on the affected side. What is the appropriate action?

Correct answer: B. Refer him to his physician

• A. Prescribing antibiotics for a condition outside your scope, without a diagnosis you are qualified to make, is inappropriate and delays proper care.
• B. CORRECT. The swelling has an identified non-dental cause and this patient has no dental disease. An arthropod envenomation with spreading facial oedema is a medical problem — necrotic arachnidism and secondary cellulitis both need medical assessment. Recognising the limits of dental scope of practice and referring is the correct professional response.
• C. Imaging is reasonable only if the history suggested a dental origin. Here the cause is visible and non-dental, and radiographs would only delay the referral.
• D. There is no odontogenic abscess to drain. Incising an envenomation site risks spreading tissue damage.

Note: A useful screen: does the presenting complaint have a plausible odontogenic explanation? Intact dentition, no caries, no periodontal disease, no recent dental treatment, plus an identified external cause equals refer. The dentist's obligation is to recognise the boundary, not to treat up to it.