commonly implicated include tuna, mackerel, sardine, anchovy, herring, bluefish, amberjack and marlin. These fish naturally have high levels of the amino acid histidine, which is converted to histamine when bacterial growth occurs during improper storage. Subsequent cooking, smoking, canning or freezing does not eliminate the histamine. Diagnosis Diagnosis of fish allergy is based on the person's history of allergic reactions, skin prick test and measurement of fish-specific serum immunoglobulin E (IgE or sIgE). Confirmation is by double-blind, placebo-controlled food challenges. Self-reported fish allergy often fails to be confirmed by food challenge. Prevention When fish is introduced to a baby's diet, it is thought to affect risk of developing allergy, but there are contradictory recommendations. Reviews of allergens in general stated that introducing solid foods at 4–6 months may result in the lowest subsequent allergy risk. Reviews specific to when fish is introduced to the diet state that fish consumption during the first year of life reduce the subsequent risks of eczema and allergic rhinitis, but maternal consumption during pregnancy had no such effect. Treatment Treatment for accidental ingestion of fish products by allergic individuals varies depending on the sensitivity of the person. An antihistamine such as diphenhydramine may be prescribed. Sometimes prednisone will be prescribed to prevent a possible late phase Type I hypersensitivity reaction. Severe allergic reactions (anaphalaxis) may require treatment with an epinephrine pen, which is an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. Unlike for egg allergy, for which there is active research on trying oral immunotherapy (OIT) to desensitize people to egg allergens, a 2015 review mentioned that there are no published clinical trials evaluating oral immunotherapy for fish allergy. Prognosis Unlike milk and egg allergies, fish allergy usually persists into adulthood. Epidemiology Incidence and prevalence are terms commonly used in describing disease epidemiology. Incidence is newly diagnosed cases, which can be expressed as new cases per year per million people. Prevalence is the number of cases alive, expressible as existing cases per million people during a period of time. Reviews cite self-reported fish allergy in range of 0 to 2.5% in the general population. Self-reported allergy prevalence is always higher than food-challenge confirmed allergy, which two reviews put at 0.1% and 0.3%, respectively. Regulation Whether food allergy prevalence is increasing or not, food allergy awareness has definitely increased, with impacts on the quality of life for children,