Step 1: Recall the diagnostic criteria of Kawasaki disease.
Fever ≥ 5 days plus ≥ 4 of: (1) bilateral non-purulent (non-exudative) bulbar conjunctival injection, (2) oral mucosal changes - cracked red lips, strawberry tongue, (3) polymorphous rash, (4) extremity changes - erythema/oedema then periungual peeling, (5) cervical lymphadenopathy (≥ 1.5 cm, usually unilateral).
Step 2: Pick the odd one out.
The conjunctivitis of Kawasaki disease is characteristically non-purulent / non-exudative, with limbal sparing and no discharge. Purulent conjunctivitis is NOT a feature - its presence should prompt a search for an alternative infective diagnosis.
Step 3: Confirm the others.
Bilateral non-exudative conjunctival injection, strawberry tongue/cracked lips, and cervical lymphadenopathy are all genuine criteria.
Key fact: Kawasaki conjunctivitis is bilateral, bulbar, and non-purulent; pus/discharge argues against the diagnosis.