Original Article
Coconut allergy: Characteristics of reactions and diagnostic predictors in a pediatric tertiary care center

https://doi.org/10.1016/j.anai.2021.01.027Get rights and content

Abstract

Background

Little is known on the clinical manifestations of coconut allergy. Our knowledge to date is mainly based on case reports.

Objective

To characterize the allergic reactions to coconut and suggest diagnostic cutoffs for specific immunoglobulin E (sIgE) and skin prick testing (SPT) to predict clinically reactive coconut allergy.

Methods

Methods include retrospective chart review at an urban tertiary care center of patients with positive testing result for coconut. Probability curves were computed by logistic regression for SPT and coconut sIgE.

Results

Of 275 records reviewed, 69 patients reported coconut reactions and 206 were sensitized only or nonallergic. The reactions occurred with breastfeeding (n = 2), contact (n = 10), or oral ingestion (n = 57). Approximately 50% of oral ingestion reactions were associated with mild/moderate anaphylaxis. Clinical reactivity vs sensitization was more common in topical coconut users (2-fold) (P = .02). Although not statistically significant, there was a trend toward more coconut allergy vs sensitization in Asian and African American patients. The probability of allergy with positive SPT result was approximately 50% and with sIgE was approximately 60%. At an SPT of 9 mm wheal or sIgE of 58 kU of allergen/L, there is a 95% probability of reaction. Cosensitization with tree nuts, legumes, and seeds was common. Macadamia nut had the strongest correlation with coconut (r = 0.81, P < .001, n = 101).

Conclusion

Although the rate of reactivity to coconut in sensitized individuals is low, half of the reactions from consumption met the criteria for anaphylaxis. Clinicians should be aware of the spectrum of reactions and diagnostic use of sIgE and SPT.

Introduction

Coconut allergy is becoming a more common concern among parents of children with food allergy, in part owing to the required labeling on packaged foods.1 In addition, coconut has increasingly become part of the US diet and is a nutritional alternative beverage for children with cow's milk allergy. It is striking that coconut is the most common food allergen present in commercially available skin care products, with 1 study revealing approximately 75% of shampoos and body soaps contain coconut.2 Furthermore, coconut has been popularized as a natural moisturizer for babies, particularly children with atopic dermatitis at high risk for food allergy.3 In infants, applying coconut to inflamed skin and not engaging in oral consumption is a concerning set-up for percutaneous sensitization and ultimately food allergy, not oral tolerance.4, 5, 6

Importantly, coconut (Cocos nucifera) is a fruit and not a tree nut, a misconception perpetuated by the Food Allergen Labeling and Consumer Protection Act which requires coconut labeling on packaged foods.7 We have observed that coconut is often tested in evaluation of tree nut allergies likely because it is included in tree nut allergen panels. In a study of children with allergy to tree nut, coconut sensitization was reported to be approximately 30% in 298 children7 and approximately 20% in another study of 191 children with sesame and tree nut allergy, with a 25% patient-reported rate of allergic reactions.1 Although reaction characteristics have been described in published case reports and case series,10, 11, 12, 13, 14, 8, 9 diagnostic cutoffs associated with reactions on specific immunoglobulin E (sIgE) and skin prick testing (SPT) have not been established.

Given our institutional experience and the paucity of literature on this topic, we sought to: (1) characterize the spectrum of reactions to coconut from a US cohort and (2) assess for possible diagnostic cutoffs for sIgE and SPT that may correlate with clinically relevant coconut allergy.

Section snippets

Chart Review

After the institutional review board approval, we retrospectively identified patients who were evaluated in the allergy clinic at Ann & Robert H. Lurie Children’s Hospital of Chicago between January 1, 2002, and August 1, 2017, and had sensitization (≥0.1 kU of allergen/L [kUa/L] for sIgE or ≥3 mm wheal to bifurcated needle on SPT) to coconut. Patients were excluded if they had no clinical notes in the medical record. Medical records including clinical notes, demographic information, and

Patient Characteristics

We identified 275 patients with positive coconut allergen testing result either by means of SPT or sIgE who had been evaluated in our allergy clinic. In reviewing the chart of the initial encounter for coconut allergy evaluation, we found that 69 (25%) had a history of contact/ingestion with reaction, 9 (3%) had ingested without reaction, and 197 (72%) were sensitized with no known history of ingestion. Average SPT wheal size between these groups ± SD was 7.67 ± 3.92 (n = 30), 4.75 ± 2.87 (n =

Discussion

This is the most comprehensive report to date revealing the gamut of reactions to coconut reported at a pediatric tertiary care center that can occur by means of skin contact, breastfeeding, or ingestion. Reactions can present as atopic dermatitis flare, urticaria, mild oral symptoms, and mild/moderate anaphylaxis. No reactions by means of skin contact or breastfeeding resulted in anaphylaxis. Sensitization to coconut as determined by SPT and sIgE is associated with an approximately 50% and 60%

References (27)

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Disclosures: The authors have no conflicts of interest to report.

Funding: The authors have no funding sources to report.

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