Cross-reactivity among tree nuts in food allergy

One third of all food allergen anaphylactic events are related to tree nut ingestion. Tree nut is not a singular allergen like the other allergens—we use the term “tree nut” to refer to 19 items! http://bit.ly/2DnkPP5

With few exceptions, peanut antigens did not serologically cross-react with tree nuts. There is some limited peanut cross-reactivity with pistachio and walnut

Walnut, pecan, and hazelnut form a group of strongly cross-reactive tree nuts.

Hazelnut, cashew, Brazil nut, pistachio, and almond form a group of moderately cross-reactive tree nuts.

Cross-reactivities between these groups are less pronounced (there is limited cross-reactivity of walnut and pecan with Brazil nut).

The strongest cross-reactivities among tree nuts follow botanical family associations:

- walnut and pecan in the family Juglandaceae
- cashew and pistachio in the family Anacardiaceae

8 foods cause 90% of food allergies (click to enlarge the image). The likelihood of a negative oral food challenge is shown in relation to the respective values of skin prick test (SPT) and serum IgE (sIgE):



References

Cross-reactivity among edible nuts: double immunodiffusion, crossed immunoelectrophoresis, and human specific igE serologic surveys. Goetz DW, Whisman BA, Goetz AD. Ann Allergy Asthma Immunol. 2005 Jul;95(1):45-52.
Figure: http://j.mp/porfbC
Image source: Wikipedia, GNU Free Documentation License.

Comments from Twitter

Matthew Bowdish MD @MatthewBowdish: This is always a conundrum for me. Pt with rxn & strong (+) to 1 tree nut but eating others without adv effect. What do you recommend?