Scombroid is a foodborne illness that results from eating improperly handled fish. Due to a disruption in the cold chain, these fish have high histamine levels. As a result, scombroid presents with allergy-like symptoms but is not really an allergy per se. Cases have been reported in many countries. Here, we report two cases of a 48 and 17-year-old father and son in Singapore who developed symptoms suggestive of scombroid after eating tuna imported from Vietnam delivered by an internationally known supply company. The diagnosis was confirmed by elevated histamine levels measured in the culprit fish product. We discuss the pathophysiology, signs, symptoms, and management of scombroid.

People eat many varieties of food to satiate their hunger. Among them, a few numbers of food cause overreaction of the body\'s immune system, and fish holds a permanent position on that list. Processing methods, including one treatment or a combination, can have different effects on the allergenic potential of food proteins. An important point to note, however, is that not all of these methods can eliminate the potential for protein allergy. Thus, it is essential to understand the risk involved with the consumption of processed fish and its derivatives. Fish could be prepared in various ways before come to the dining plate. It has shown some of these methods can effectively manipulate the allergenicity owing to the alterations occurred in the protein conformation. This article provides an overview of the impact of fish processing methods (thermal and non-thermal) on the allergenic potential of fish along with possible causative structural modification provokes allergen stability. The article begins with current trends related to fish consumption, proceeds with the prevalence and underlying mechanism of fish allergy. Properties of clinically relevant fish proteins, projected IgE epitopes of PV, cross-reactivity of fish allergens are also addressed in this context to understand and compare the behavioral patterns of PV profiles of different species on processing methods.

Seafood refers to several distinct groups of edible aquatic animals including fish, crustacean, and mollusc. The two invertebrate groups of crustacean and mollusc are, for culinary reasons, often combined as shellfish but belong to two very different phyla. The evolutionary and taxonomic diversity of the various consumed seafood species poses a challenge in the identification and characterisation of the major and minor allergens critical for reliable diagnostics and therapeutic treatments. Many allergenic proteins are very different between these groups; however, some pan-allergens, including parvalbumin, tropomyosin and arginine kinase, seem to induce immunological and clinical cross-reactivity. This extensive review details the advances in the bio-molecular characterisation of 20 allergenic proteins within the three distinct seafood groups; fish, crustacean and molluscs. Furthermore, the structural and biochemical properties of the major allergens are described to highlight the immunological and subsequent clinical cross-reactivities. A comprehensive list of purified and recombinant allergens is provided, and the applications of component-resolved diagnostics and current therapeutic developments are discussed.

Seafood allergies have been increasing their presence in the last 2 decades. Allergic reactions to seafood can range from mild urticarial and oral allergy syndrome to life-threatening anaphylactic reactions. Ingestion of seafood infested with Anisakis larvae can cause a disease known as anisakiasis with symptoms similar to true seafood allergy. Furthermore, some adverse reactions to seafood including histamine fish poisoning (HFP), and intolerance to histamine can trigger clinical symptoms, which, although nonallergic in origin, are similar to true immunoglobulin E (IgE)-mediated allergic reactions. Because seafood allergy usually remains a lifelong food allergy, this review focuses on the current knowledge on fish and shellfish allergens and emphasizes the importance of differentiating seafood allergy from other allergy-like reactions (anisakiasis, HFP, and intolerance to histamine). Key teaching points: • Fish and shellfish are potent allergens that can provoke serious IgE antibody-mediated adverse reactions in sensitive individuals. • Sensitization to seafood allergens can be achieved by ingestion, inhalation, or skin contact. • Shellfish major allergen, tropomyosin, shares significant homology to arthropods (dust mites and cockroaches). • Accidental exposures to seafood products cross-contaminated with fish or shellfish allergens (hidden allergens) during processing may present a health risk for sensitive individuals. • Allergens of fish parasite A. simplex present common hidden allergens in seafood, particularly in raw and undercooked home-made fish dishes. • Symptoms caused by HFP, histamine intolerance, and anisakiasis are similar to true seafood allergy.