Kiwi fruit is a significant allergen and is associated with differing patterns of reactivity in children and adults

Allergy to kiwi fruit appears increasingly common, but few studies have evaluated its clinical characteristics, or evaluated methods of investigating the allergy.

To characterize the clinical characteristics of kiwi fruit allergy and to study the role of double-blind placebo-controlled food challenge (DBPCFC), skin tests and specific IgE in the diagnosis of this food allergy.

Two-hundred and seventy-three subjects with a history suggestive of allergy to kiwi completed a questionnaire. Forty-five were investigated by DBPCFC, prick-to-prick skin testing with fresh kiwi pulp, and specific IgE measurement. Nineteen subjects were also skin tested using a commercially available solution.

The most frequently reported symptoms were localized to the oral mucosa (65%), but severe symptoms (wheeze, cyanosis or collapse) were reported by 18% of subjects. Young children were significantly more likely than adults to react on their first known exposure (P<0.001), and to report severe symptoms (P=0.008). Twenty-four of 45 subjects (53%) had allergy confirmed by DBPCFC. Prick-to-prick skin test with fresh kiwi was positive in 93% of subjects who had allergy confirmed by DBPCFC, and also in 55% of subjects with a negative food challenge. The commercial extract was significantly less sensitive, but with fewer false-positive reactions. CAP sIgE was only positive in 54% of subjects who had a positive challenge.

Kiwi fruit should be considered a significant food allergen, capable of causing severe reactions, particularly in young children. DBPCFC confirmed allergy to kiwi fruit in 53% of the subjects tested, who had a previous history suggestive of kiwi allergy. Skin testing with fresh fruit has good sensitivity (93%), but poor specificity (45%) in this population. CAP sIgE and a commercially available skin test solution were both much less sensitive (54%; 75%) but had better specificity (90%; 67%).