Fish allergy is an immune hypersensitivity to proteins found in fish. Symptoms can be either rapid or gradual in onset. The latter can take hours to days to appear. The former may include anaphylaxis, a potentially life-threatening condition which requires treatment with epinephrine. Other presentations may include atopic dermatitis or inflammation of the esophagus. Fish is one of the eight common food allergens which are responsible for 90% of allergic reactions to foods: cow's milk, eggs, wheat, shellfish, peanuts, tree nuts, fish, and soy beans. Unlike early childhood allergic reactions to milk and eggs, which often lessen as the children age, fish allergy tends to first appear in school-age children and persist in adulthood. Strong predictors for adult-persistence are anaphylaxis, high fish-specific serum immunoglobulin E (IgE) and robust response to the skin prick test. It is unclear if the early introduction of fish to the diet of babies aged 4–6 months decreases the risk of later development of fish allergy. Adult onset of fish allergy is common in workers in the fish catching and processing industry. Signs and symptoms Food allergies in general usually have an onset of symptoms in the range of minutes to hours for an IgE-mediated response, which may include anaphylaxis. Symptoms may include rash, hives, itching of mouth, lips, tongue, throat, eyes, skin, or other areas, swelling of lips, tongue, eyelids, or the whole face, difficulty swallowing, runny or congested nose, hoarse voice, wheezing, shortness of breath, diarrhea, abdominal pain, lightheadedness, fainting, nausea, or vomiting. Non-IgE-mediated responses occur hours to days after consuming the allergenic food, and are not as severe as IgE-mediated symptoms. Symptoms of allergies vary from person to person and incident to incident. Potentially life-threatening, the anaphylactic onset of an allergic reaction is characterized by respiratory distress, as indicated by wheezing, breathing difficulty, and cyanosis, and also circulatory impairment that can include a weak pulse, pale skin, and fainting. This can occur when IgE antibodies are released and areas of the body not in direct contact with the food allergen show severe symptoms. Untreated, the overall response can lead to vasodilation, which can be a low blood pressure situation called anaphylactic shock. Causes Eating fish The cause is typically the eating of fish or foods that contain fish. Once an allergic reaction has occurred it usually remains a lifelong sensitivity. Briefly, the immune system overreacts to proteins found in fish, primarily to parvalbumin,