Anaphylaxis and allergy to coconut: An Australian pediatric case series

Prevalence and burden of coconut allergy in the United States

BACKGROUND

Epidemiologic data on coconut allergy remains sparse in the United States despite the labeling requirement by the Food Allergen Labeling and Consumer Protection Act for products containing coconut.

OBJECTIVE

To provide current estimates of the prevalence, severity, determinants, and distribution of coconut allergy in the United States.

METHODS

A comprehensive food allergy prevalence survey was administered to a nationally representative, probability-based sample of US households between October 1, 2015 and September 30, 2016. Eligible respondents included adults who were able to complete self- and parent-proxy report surveys in English or Spanish by means of web or phone.

RESULTS

Using survey responses from 78,851 individuals, 0.39% (95% confidence interval [CI], 0.33-0.45) of the US general population were categorized as having convincing coconut allergy. Among children, 0.22% (95% CI, 0.16-0.30) were estimated to have coconut allergy compared with 0.43% (95% CI, 0.37-0.51) of adults, whereas only 0.12% (95% CI, 0.08-0.18) of these children and 0.20% (95% CI, 0.16-0.24) of adults with convincing immunoglobulin E (IgE)-mediated coconut allergy reported physician-confirmed diagnoses. A current epinephrine prescription was reported by 40.1% (95% CI, 33.3-47.4) of those with convincing coconut allergy. Reactions involving multiple organ systems were reported by 47.5% (95% CI, 40.1-54.9) of those with convincing coconut allergy.

CONCLUSION

Roughly 1 in 260 Americans report symptoms consistent with an IgE-mediated allergy to coconut, although fewer than half of these individuals report receiving a physician diagnosis. Our data indicate that most individuals with reported coconut allergy meeting symptom-based criteria for convincingly IgE-mediated disease have comorbid FAs, and for many patients, clinical management seems to be suboptimal.

Identification of allergens in coconut milk and oil with patients sensitized to coconut milk in Sri Lanka

BACKGROUND

Despite the low prevalence of IgE sensitivity to fresh or boiled coconut milk and coconut oil, those may contain allergens of which the clinical significance remains undetermined. This study aimed to identify and compare allergens in fresh coconut milk (FCM), boiled coconut milk (BCM), unrefined wet-processed coconut oil (WPCO), and dry-processed coconut oil (DPCO) using sera from patients with allergy to coconut milk.

METHODS

The study included 18 patients with immediate hypersensitivity to coconut milk, including five who developed anaphylaxis. Sensitization was assessed by skin prick test and ImmunoCAPs using commercially available coconut extracts. Immunoblotting was performed to identify and compare allergen profiles.

RESULTS

Total sIgE levels and overall IgE reactivity of patients with anaphylaxis were higher compared to patients with allergy. Twelve allergens ranging from 5 to 128 kDa including six novel allergens with 5, 12, 47, 87, 110, and 128 kDa were visualized in immunoblots with FCM. Similarly, nine allergens of 5, 12, 17, 32, 35, 47, 87, 110, and 128 kDa were detected in BCM. One allergen (110 kDa) was discerned in all four extracts. Higher IgE prevalence was detected with three allergens of 55, 87, and 110 kDa.

CONCLUSIONS

Allergens of BCM and unrefined coconut oil (WPCO and DPCO) were determined for the first time. Novel allergens of 87 and 110 kDa and the 55 kDa allergen have the highest potential to be used in Component Resolved Diagnostics. Further, these findings demonstrate that, patients who have an allergy to coconut milk could also react to boiled coconut milk and unrefined coconut oil.

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

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.