Scientific Study

BACKGROUND: Peanut allergy frequently cause severe allergic reactions. Diagnosis include detection of IgE to peanuts in serum or by skin prick tests. While children may have allergic sensitisation without having clinical peanut allergy, oral peanut challenge is often required for accurate diagnosis. The conjunctival provocation test is used for diagnosis and evaluation of treatment effect in inhalant allergies, but it has not been evaluated as a tool for diagnosing peanut allergy. OBJECTIVE: To investigate if the conjunctival provocation tests may be feasible, accurate and safe in diagnosing clinically relevant peanut allergy in patients with suspected peanut allergy. METHODS: This cross-sectional case-control study in children with clinical or laboratory suspected peanut allergy included 102 children recruited from the regional paediatric departments and specialist practices during one year from April 2011. A peanut tolerant control group of 28 children of similar age was recruited locally. A double-blind placebo-controlled conjunctival provocation test with peanut extract was performed in all children, while oral peanut provocation was performed as double-blind placebo-controlled challenge in children with suspected peanut allergy and as an open challenge in the control children. RESULTS: All 81 children with a positive double-blind placebo-controlled oral food challenge also had a positive conjunctival provocation test. None of the children with negative conjunctival provocation test had a positive oral food challenge. The sensitivity and the specificity of the conjunctival provocation test was 0.96 and 0.83 respectively. No children had severe adverse reaction caused by the conjunctival provocation test, whereas 23 children suffered an anaphylactic reaction to the oral food challenge. CONCLUSION & CLINICAL RELEVANCE: Conjunctival allergen challenge appears to be a feasible, accurate and safe in diagnosing children referred for suspected peanut allergy.