Published Online: July 2013
The diagnosis of peanut allergy often results in tremendous changes in quality of life, because dietary restrictions are necessary and preparations to treat anaphylaxis with epinephrine self-injectors are required. Therefore, a precise diagnosis is mandatory. Laboratory tests are often insufficient as a sole means to diagnose peanut allergy and medically supervised oral food challenge are frequently needed. The food challenge is, unfortunately, time consuming, stressful, and risky, underscoring the need for more definitive, simple diagnostic tests. Recently, improved laboratory-based diagnostic tests for peanut allergy using the determination of allergic antibodies against specific individual peanut proteins (component tests), especially Ara h 2, have been proposed to improve the diagnostic work-up.
A recent study published in The Journal of Allergy and Clinical Immunology: In Practice, by Lopes de Oliveira et al, investigated the usefulness of peanut-specific allergic antibody levels for the diagnosis of peanut allergy. They evaluated a specific modality, the ISAC-Immuno Solid-phase Allergen Chip to determine allergic antibody binding to individual peanut proteins, and also performed standard serologic tests to peanut. They compared the laboratory results of these modalities to the outcomes of oral food challenges performed in 61 German children referred to a tertiary allergy center with suspected peanut allergy.
Overall, 34 of the 61 patients were peanut allergic. Neither the level of allergic antibodies measured by the standard serologic test, nor to the individual proteins in the ISAC test were able to clearly distinguish allergic from non-allergic patients, although children with strong positive tests were more likely to be allergic. For example, although 94% of the peanut allergic patients showed binding of allergic antibodies to the specific peanut allergen Ara h 2, 26% of non-allergic patients did as well.
The authors concluded from these results that oral food challenges remain the gold-standard method for a precise diagnosis of peanut allergy.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.