food allergy

Nut-Induced Anaphylaxis Risk Is Elevated During Halloween and Easter

Children with nut allergies are at a higher risk of anaphylaxis during Halloween and Easter than other holidays or times of the year, a recent study indicated.

“Although specific periods in the year such as holidays are expected to be associated with a higher risk of accidental reactions to peanuts and tree nuts, to our knowledge, there are currently no data assessing this risk. Identifying certain times associated with an increased risk of anaphylaxis could help to raise community awareness, support, and vigilance. This information would identify the best timing for public awareness campaigns to prevent allergic reactions” the study authors noted.

To conduct their study, the researchers collected data from 1390 pediatric cases in which patients presented to the emergency department with anaphylaxis between April 2011 and January 2020. Anaphylaxis was defined as a reaction to food involving at least 2 organ systems or hypotension. The data was collected from 4 of the 10 Canadian provinces: Quebec, Ontario, Newfoundland, and Labrador. All participants were younger than 18 years of age (median age 5.4 years) and 62.2% (864) of participants were boys.

Data was collected using a standardized data entry form that included the patient’s sex, age, date of presentation to the emergency department, reported trigger food, history of known nut allergy, presence of comorbidities, and clinical characteristics and management. Also included on the form were 3 categories for the reported trigger foods: unknown nuts, peanuts, and tree nuts.

The severity of the allergic reaction was categorized as mild, moderate, or severe, using a modified grading system. Mild reactions included generalized pruritis, flushing urticaria, angioedema, nausea or emesis, mild abdominal pain, nasal congestion or sneezing or both, rhinorrhea, throat tightness, mild wheezing, tachycardia, or anxiety. Symptoms associated with moderate reactions included crampy abdominal pain, diarrhea, recurrent vomiting, hoarseness, “barky cough,” difficulty swallowing, dyspnea, moderate wheezing, or light-headedness. Severe reactions were defined as a loss of bowel control, cyanosis, respiratory arrest, hypotension or circulatory collapse or both, dysrhythmia, severe bradycardia or cardiac arrest or both, confusion, or loss of consciousness.

Using a Poisson regression model, the researchers compared the mean number of nut-induced anaphylaxis from Halloween, Christmas, Easter, Diwali, Chinese New Year, Eid al-Adha, and the rest of the year. The researchers also assessed the mean number of instances of anaphylaxis in the week following each holiday.

During Halloween and Easter there was an increase of about 70% in cases of anaphylaxis induced by unknown nuts (incidence rate ratio [IRR] 1.66; 95% CI, 1.13-2.43) compared to the rest of the year. For peanut-triggered anaphylaxis, there was an increase of 85% (IRR 1.86; 95% CI,1.12-3.11) during Halloween and 60% during Easter (IRR 1.57; 95%CI, 0.94-2.63). There was no observed change for anaphylaxis triggered by tree nuts during holidays in comparison with the rest of the year.

“The difference in the anaphylaxis incidence among holidays may have been due to the social setting in which each holiday takes place. At Halloween and Easter, children often receive candies and other treats from people who may be unaware of their allergies. The absence of such an association at Christmas may be because Christmas is a more intimate celebration among family members and close friends, who are more vigilant regarding allergen exposure.”

“We found an increased risk of anaphylaxis induced by unknown nuts and peanuts during Halloween and Easter among Canadian children. We also found that the holiday period particularly affected older children. Educational programs and strategies increasing vigilance among families of children with peanut or tree nut allergy and among people interacting with them are required in order to render holidays safer for all Canadian children,” the researchers concluded.

—Leigh Precopio



Leung M, Clarke AE, Gabrielli S, et al. Risk of peanut- and tree-nut-induced anaphylaxis during Halloween, Easter and other cultural holidays in Canadian children. CMAJ.  2020;192(38):1084-1092. Doi: 10.1503/cmaj.200034