Table 1 Inclusion and exclusion criteria

Inclusion criteria - all of:

Diagnosed by the treating doctor with ulcerative pharyngitis, herpangina, hand foot and mouth disease, herpetic gingivostomatitis OR non-herpetic gingivostomatitis

Parental complaint of child's poor oral intake

Intake of less than 10 ml/kg of fluid within 2 hours preceding presentation to RCH ED

Exclusion criteria - any of:

Presence of more than 2 vomits within 24 hours preceding presentation to RCH ED

Presence of active painful dental disease (caries, dental abscess) or painful recent mouth trauma, mouth burn, or post-operative state (minimum of 5 days)

Systemic toxicity related to infection, as defined by the treating doctor

Severe dehydration requiring immediate therapy, as defined by the treating doctor

Known allergy to local anaesthetic, gelatine, methylcellulose, cherry flavouring, paracetamol or ibuprofen

Chronic renal or liver impairment

History of epilepsy or cardiac disease

Presence of acute porphyria

Presence of malignancy

Current use of anti-arrhythmic drugs, xylocaine, phenytoin, cimetidine or beta-blockers, warfarin, lithium, angiotensin converting enzyme (ACE) inhibitors, thiazide diuretics, frusemide, aspirin, salicylates, probenecid, anti-diabetic medications, zidovudine, cardiac glycosides or methotrexate

More than 1 dose of 2% viscous lignocaine or medications containing lignocaine as the active ingredient for this episode of illness

Pre-existing upper airway obstruction and/or swallowing difficulties

Analgesia taken within 1 hour preceding enrolment to study

Non-English speaking parents/guardians