The investigators will conduct low-dose intranasal allergen challenges on children/adolescents with a diagnosis of food allergy to egg/cow's milk/soya/wheat/peanut. The data will be used to determine the safety and potential utility of intranasal food challenges in the diagnosis of food allergy.

Inclusion Criteria:

• Aged 6 - 17 years old

• Physician-diagnosis of food allergy on the basis of:

  • Positive oral food challenge to the causative food (conducted under medical supervision) within the last 12 months; OR
  • History of convincing clinical reaction to the causative food within the last 12 months AND positive skin prick test within last 12 months; OR
  • Evidence of >95% likelihood of food allergy (on the basis of serum specific IgE or skin prick test (SPT) 8mm or above to the causative food allergen within past 12 months

• Written informed consent from parent/guardian, with assent from children aged 8 years and above wherever possible. Participants aged over 16 years will need to provide their owned informed consent.

Exclusion Criteria:

• Contraindicated as acutely unwell or current unstable asthma:

  • Acute wheeze in last 72 hours requiring treatment
  • Febrile ≥38.0oC in last 72 hours
  • Recent admission to hospital in last 2 weeks for acute asthma

• Current medication

  • Use of asthma reliever medication in last 72 hours
  • Recent administration of a medication containing antihistamine within the last 4 days
  • Current oral steroid for asthma exacerbation or course completed within last 2 weeks