PURPOSE OF THE STUDY.
The prevalence of self-reported seafood allergy in children is significantly less than in adults. There are limited recent published data on children with seafood allergy. The objective of this study was to clarify the clinical characteristics of seafood allergy among children.
The study included 167 children, age range 10 months to 4 years, who presented to the allergy clinic of a children’s hospital in Australia between 2006 and 2009 with a history of clinical reaction to seafood exposure and confirmation of immunoglobulin E (IgE) sensitization, or a positive food challenge to seafood.
Retrospective chart review. Sensitization was assessed by prick skin tests (PST) rather than serum-specific IgE because of the lack of commercial tests for most Australian fish and lack of cutoff values predicting clinical reactivity for seafood other than cod. Standard definitions of a positive PST were used. Specific allergens tested were based on individual circumstances and included fresh and/or canned fish in many patients. Reactions were classified as localized contact, mild-moderate systemic (cutaneous, gastrointestinal [GI]), or anaphylactic (respiratory of cardiovascular symptoms).
Ninety-four percent of patients had preexisting atopy. Prawn (27% of patients), “white fish” (10%), and salmon and tuna (8%) were the most common seafood allergens. Less than 5% were allergic to mollusks. Twenty-one percent had previous anaphylaxis to seafood. Most patients had urticaria/angioedema with 20% having GI symptoms. Sixteen percent had ocular or upper respiratory symptoms with exposure to vapors from seafood. Concurrent asthma was found to be a risk factor (odds ratio of anaphylaxis, 2.4). History of reactions to vapors and previous anaphylaxis to nonseafood allergens was not a risk factor for anaphylaxis. Skin test size was not a predictor of reaction severity. A history of anaphylaxis occurred in ∼20% of those with crustacean and fish allergy but none with mollusk allergy. Cross-sensitization to other classes of shellfish and fish were common, many of whom were also clinically reactive, but at least 50% of crustacean-allergic children could tolerate fish. Only ∼5% of fish allergic patients had clinical reactivity to crustaceans. Approximately one-third of fish allergic patients could tolerate canned fish. Seafood allergy resolved in 4% of children; PST remained mildly positive in most.
In Australia, seafood is a common cause of food allergy and is associated with a fivefold higher chance of anaphylaxis compared with other food allergies. There is also a high degree of cross-sensitization between Crustacean and fish, as well as clinical cross-reactivity. Children with seafood allergy have a higher incidence of other atopic diseases compared with peanut-allergic children. Children with fish allergy may be able to tolerate canned fish, but tolerance must be proven first.
This study offers important advice for the clinical management of seafood allergy. This study also offers additional evidence that children with fish allergy may also be allergic to shellfish. Shortcomings of this study include a lack of standardized skin test panels to evaluate cross-reactivity and other allergic sensitivities that may be related.
- Copyright © 2012 by the American Academy of Pediatrics