A practical focus on oral immunotherapy to tree nuts.

Tree nut (TN) allergy is common, with a global prevalence of up to 4.9%. TN allergy is persistent in most patients, and accidental reactions are common. There is considerable clinical cross-reactivity between cashew and pistachio, and between walnut and pecan. A diagnosis of TN allergy is based on a history of clinical reaction on ingestion, along with confirmed sensitization through either skin-prick or serum immunoglobulin E (IgE) testing. Component testing and food challenges may be required in patients with birch pollinosis to distinguish between IgE-mediated allergy to a heat-stable protein and pollen food allergy syndrome. There is available evidence that TN oral immunotherapy (OIT) is reasonably safe and effective. There are numerous nonpharmaceutical food products to facilitate TN-OIT dosing. TN OIT should be offered as a treatment option for patients with TN allergy.