It is evident from both longitudinal and cross sectional studies of peanut allergy that the allergy fades in up to 20% of children. This does not mean that other nut or food allergies in a peanut allergic child will fade simultaneously. Although a direct or accidental challenge is the most reliable method of identifying individuals with peanut or nut allergy, the size of the reaction on skin testing is a reliable guide to the risk.

Parents need to know that the wheal size on skin testing and the risk of a severe reaction varies with age in children. An average figure of 6x6 mm is used to define a those that will definitely react but in babies skin test wheals of 4x4 mm can be associated with life-threatening reactions.