Associate Professor Andreas Lopata from Melbourne's RMIT University, and his colleague Samuel Lehrer from Tulane University, New Orleans, have recently published a review of current literature in the field of seafood allergy. The review covers a wide range of topics: epidemiology and prevalence; clinical features and diagnostic approaches of seafood allergy; allergens in the different seafood groups; cross-reactivity with other allergen sources; sensitisation and provocation routes; and treatment and management of seafood allergy.

With the consumption of seafood having increased worldwide and the prevalence of seafood allergy being higher when consumption plays a greater part in the diet, reports of adverse reactions becoming more frequent are to be expected. Indeed, the authors cite a recent analysis of food-related reactions in emergency departments in the USA which established that shellfish was the most frequently implicated food in persons aged 6 years or older. In addition, patients with fish or shellfish allergy, similar to peanut allergy, will mostly remain clinically reactive throughout their life.

It is not just western countries that are seeing an increase in seafood allergies. Given the high consumption of seafood in Asian countries, allergic reactions to seafood and particularly shellfish are increasingly significant among children and adults in those countries.

Much work has focused on identifying and characterising the specific allergenic proteins within the fish and shellfish in the past 2 years. In this time, over 10 additional seafood allergens have been characterised, and while this has lead to more allergen-specific detection assays for detecting the presence of these allergens in food products, many specific mollusk and some fish allergens are not yet identified. Likewise, there is little information on the establishment of threshold values for elucidating allergic reactions to seafood. One recent study mentioned in the review demonstrated that for codfish, amounts of less than 3mg protein could trigger allergic reactions, which is less than that previously reported.

The authors highlight many interesting findings in relation to cross-reactivity of allergens within the seafood species and also with other unrelated allergen sources such as house dust mites and cockroaches.

The review provides a useful list of papers of particular interest in this field. Those of special interest and outstanding interest have been highlighted.

Reference: Lopata and Lehrer. 2009. Current Opinion in Allergy and Clinical Immunology. Vol. 9 pp. 270–277.