It is estimated that up to 0.2 percent of the general population is affected by fish allergy.1,2 Fish allergy does occur in children, but is more prevalent in adolescents and adults: Nearly 40 percent of patients with fish allergy first react during adulthood.3 Because fish allergy is often noted in adults, it is considered a life-long allergy that is not usually outgrown.3-5
Patients become sensitized to fish in the following ways: By exposure via the gastrointestinal tract during ingestion (the major route of sensitization), via the respiratory system by aeroallergens (an important trigger of atopic dermatitis), or by skin contact.2 For 8.6 percent of patients with fish allergy, the worst reactions were to skin contact and/or inhalation, and some of these patients were able to eat fish without reaction.3
Seafood allergy, including fish, is potentially severe, and in some cases, can even lead to life-threatening anaphylaxis.2,3
Nearly 40 percent of patients with fish allergy first react during adulthood.3
The current clinical approach to fish allergy diagnosis includes a physical examination, skin-prick testing or specific IgE blood testing, and, in selected cases, an oral food challenge.1,2 Like all food allergies, diagnosing a fish allergy starts with a physical examination and, of critical importance, a food-allergy-focused patient history.6,7
The findings of this fish-allergy-focused patient history can be used to guide testing decisions and results interpretation.
This systematic approach can help determine whether the reported history of food allergy, combined with laboratory data, is sufficient to diagnose fish allergy, or if an oral food challenge should be considered.1,8
Identifying individuals with fish allergy is important, as these patients are at risk for severe reactions.2,3 Allergy to fish is usually lifelong, making effective and accurate diagnostic workup for seafood allergy essential for clinicians and patients.1,3-5
The evaluation for a patient with a possible food allergy begins with a thorough history and physical exam. If the clinical history suggests an IgE-mediated food allergy, skin-prick or specific IgE tests are needed to help confirm the diagnosis. Algorithm data from Niggemann and Beyer and Lopata et al.
The diagnosis of fish allergy is complicated by cross-reactivity among fish allergens.1 Clinical cross-reactivity among fish species is common, even in fish from taxonomically distinct orders.1 Patients allergic to finned fish (e.g., tuna, salmon, and cod) may need to avoid that entire food group because of high rates of cross-reactivity.5 Allergic cross-reactivity among fish is high, but variable: Patients may have clinical monosensitivity to a single fish or fish family, for example, only to swordfish.1,5,11
Adding diagnostic testing to aid in a differential diagnosis has been shown to increase confidence in diagnosis to 90 percent.i,ii Conventionally, a diagnosis of allergic or autoimmune disease relies on the case history and a physical examination. However, adding diagnostic testing to aid in a differential diagnosis has been shown to increase confidence in diagnosis.i,ii Diagnostic testing can also help to improve the patient’s quality of life and productivity, reduce costs associated with absenteeism, and optimize use of medication, in addition to decreasing unscheduled healthcare visits.iii,iv
i. Duran-Tauleria E, Vignati G, Guedan MJ, et al. The utility of specific immunoglobulin E measurements in primary care. Allergy. 2004;59 (Suppl78):35-41.
ii. NiggemannB, Nilsson M, Friedrichs F. Paediatric allergy diagnosis in primary care is improved by in vitro allergen specific IgE testing. Pediatr Allergy Immunol. 2008;19:325-331
iii. Welsh N, et al. The Benefits of Specific Immunoglobulin E Testing in the Primary Care Setting. J Am Pharm Assoc. 2006;46:627.
iv. Szeinbach SL, Williams B, Muntendam P, et al. Identification of allergic disease among users of antihistamines. J Manag Care Pharm. 2004; 10 (3): 234-238
See which labs in your region have the tests you need
Get scientific information on more than 550 allergens.
Currently, optimal management of seafood allergy does not exist. The management of fish allergy relies on the elimination of fish from the diet of the sensitized patient and symptomatic treatment of accidental allergic reactions.2, 11 As manifestations of fish allergy may be life-threatening and are frequently life-long, patients with potentially life-threatening food allergy should be prescribed an epinephrine auto-injector and educated in its use.5
Practice parameters have been developed to help guide the management and treatment of patients with food allergies, including fish.