Oral immunotherapy effectively desensitizes cashew allergy in children

Cashew oral immunotherapy desensitized most children with cashew allergy as well as those with a co-allergy to pistachio and had a similar safety profile to other food-related oral immunotherapies, according to a study published in Allergy.

Tree nut allergy is often complicated by a high rate of cross-sensitization and cross-reactivity between different nuts, so many patients with a single tree nut allergy may be instructed to eliminate multiple nuts from their diet, further impairing quality of life and possibly increasing risk for developing actual allergy, according to the study researchers.

Additionally, the researchers noted that cashew allergy is one of the most common tree nut allergies and that the increasing production of cashew nuts may create a greater risk for accidental exposure among allergic patients.

“The increase in cashew nut consumption and its availability in the diet, together with the increased prevalence and severity of cashew allergy, makes it an important therapeutic target in affected individuals,” Arnon Elizur, MD, director of the Institute of Allergy, Immunology and Pediatric Pulmonology at Yitzhak Shamir Medical Center in Zerifin, Israel, and colleagues wrote.

The researchers enrolled 50 patients aged 4 years or older (median age, 8 years; 56% boys) with cashew allergy into cashew OIT with a target dose of 4,000 mg cashew protein along with 15 patients (median age, 8.7 years; 80% boys) eligible for OIT but on a waiting list as controls.

Most patients and controls were co-allergic to pistachio and had severe cashew allergy, as approximately 40% had previous reactions treated by injectable epinephrine.

OIT began with a dose-escalation phase to establish each patient’s single highest-tolerated dose, which was then consumed at home for 24 days. This was followed by in-clinic monthly dose escalations and subsequent 24-day home consumption until reaching the goal of 4,000 mg cashew protein. Median duration of OIT, after excluding two patients who withdrew in the first week, was 12 months (range, 3-57).

Results showed that 88% of patients vs. 0% of the controls could tolerate a dose of 4,000 mg of cashew protein at the end of the study (OR = 8.3; 95% CI, 3.9-17.7). Three additional patients in the treatment group achieved partial desensitization to cashew and could tolerate 1,200 mg of cashew protein.

Of the 88% of patients who experienced adverse reactions to treatment during clinic dosing, most were mild and treated with antihistamines. Six patients required bronchodilators and nine required injectable epinephrine for clinic doses. Similarly, 52% of patients experienced mild adverse reactions for home doses, with only three patients requiring injectable epinephrine.

The 35 patients with a co-allergy to pistachio all passed an oral food challenge. The researchers did not test pistachio OFC on control patients as it was deemed nonethical considering their persistent cashew allergy and lack of significant changes in immunological parameters to pistachio.

The researchers instructed all patients who achieved full desensitization to the 4,000 mg cashew protein dose to continue long-term consumption of a 1,200 mg dose. At 6 months follow-up, all 44 patients who achieved full desensitization during the study passed OFC of 4,000 mg of cashew protein.

“Patients with tree nut allergy are often allergic to several nuts,” Elizur and colleagues wrote. “In order to improve patient compliance and quality of life, it is essential to minimize the number of OIT treatments and the number of foods that patients are required to consume long-term.”