An allergy is a misguided type-I hypersensitivity response triggered by binding of an allergen to immunoglobulin E (IgE) antibodies. Antibody reactions require a molecule of sufficient size. As a result, most allergens are large biomolecules such as proteins and carbohydrates, many of which can be removed or broken down by food processing. A smaller molecule may still become allergenic by binding to a larger molecule to form an epitope of sufficient size; such a small molecule is called a hapten.
Allergens are categorized on this page by origin for minimal redundancy. Symptoms typically depend on route of exposure, which is not yet sorted cleanly here.
The World Health Organization and International Union of Immunological Societies (WHO/IUIS) Allergen Nomenclature Sub-Committee maintains a webpage listing every protein (as well as some carbohydrates) that have elicited a confirmed IgE reaction in any human. Readers seeking a more reliable list are advised to visit their website.[3]
Present in many foods, such as coffee, flavored tea, wine, beer, gin, liqueurs, apéritifs (e.g. vermouth, bitters), soft drinks including cola, juice, citrus, citrus fruit peel, marmalade, tomatoes and tomato-containing products, Mexican and Italian foods with red sauces, ketchup, spices (e.g. cloves, Jamaica pepper (allspice), cinnamon, nutmeg, paprika, curry, anise, and ginger), chili sauce, barbecue sauce, chutney, pickles, pickled vegetables, chocolate, vanilla, baked goods and pastries, pudding, ice cream, chewing gum, and candy.
A number of national and international surveys have identified Balsam of Peru as being in the "top five" allergens causing patch test reactions in people referred to dermatology clinics.[4][5]
Allergenicity is highest in Japan and Korea.[7] It is estimated that buckwheat causes 5% of all immediate-type allergic reaction cases (from food) in Japan.[8] Hazard extends to inhalation of milled flour particles (aeroallergen). Irrespective of the nomenclature, it is not a wheaten cereal; the name refers to its viability as a pseudocereal. Relating or conflating buckwheat allergy with wheat allergy or Triticeae hypersensitivities should be avoided.[9]
Higher risk of provoking life-threatening reactions compared to most other food allergies. Celery seeds and celeriac are more allergenic than celery stalks.[11][12] Some individuals become cross-sensitized to other spices and herbs in the parsley family. Prevalence is high among adults in Central Europe. It is estimated that two-fifths of all Swiss food-allergy patients react to celery tubers and nearly a third of severe food allergy reactions in France may be due to celery.[13]
Dermatitis, rhinitis, asthma, urticaria, asymmetrical pattern of fissure, thickening/shedding of the outer skin layers,[20] rarely anaphylaxis
Very few garlic allergens have been reported, and garlic allergy has been rarely studied. Some garlic-allergic individuals may cross-react with leek, shallot and onion (other Allium). Garlic that has been heated/cooked is less allergenic than raw garlic.[21][22]
Risk extends to respiratory inhalation. Oat is not a triticeae cereal but it is possible for individuals with gluten-related disorders to be misdiagnosed as having a hypersensitivity to pure oat because cross-contamination is very common in the western world.
Risk extends to wheat hybrids like triticale.[25] True wheat allergies are very rare; it is estimated to effect 0.1%-2.2% of individuals depending on region.[26] The allergy does not commonly persist into adolescence. Gluten-free foods are safer for wheat allergic patients but they still may theoretically contain wheat's other allergenic proteins.[27] Wheat allergy symptoms should not be confused with celiac disease, gluten ataxia or non-celiac gluten sensitivity (NCGS). While wheat allergies are "true" allergies, celiac disease and gluten ataxia are an autoimmune diseases.[28] NCGS is more similar to food intolerances but as of 2021 its pathogenesis is still not well understood.
Distinct from tree nut allergy, as peanuts are legumes. Reactions are often severe or fatal.
Includes some cold-pressed peanut oils. Highly refined (hot pressed followed by further treatment) peanut oils contain almost no protein and present minimal risk.[30]
Anaphylaxis, asthma exacerbation, rhinitis, allergic conjunctivitis, hives, atopic dermatitis, swelling of, or under the dermis, diarrhea, nausea, vomiting
Overall is lower in prevalence than both peanut allergy and cow's milk allergy. However, due to similar protein structures, soya is a common cross-reactive allergen in both peanut-allergic individuals and milk-allergic individuals; especially infants.[31]
Mustard allergy onset is usually in infancy or toddlerhood;[33] it is seemingly very rare but true prevalence can not be established due to several tests producing high rates of false positives.[34] Due to a gradual increase in prevalence[35] and the severity of known reactions it became recognized as the 11th priority allergen by Canada in 2009,[36] and a top 14 priority allergen by the European Union in 2014.[37][38]
By law, foods containing sesame must be labeled so in European Union, Canada, Australia, and New Zealand.[39] Increasing prevalence has led to it being deemed the ninth most common food allergen in the United States in 2019. Highest prevalence by age was among 18-29 year olds and an estimated 80% of all sesame-allergic patients had a comorbid food allergy.[41] In 2018, the US FDA issued a request for information for the consideration of labeling for sesame to help protect people who have sesame allergies.[42] A decision was reached in November 2020 that food manufacturers voluntarily declare that when powdered sesame seeds are used as a previously unspecified spice or flavor, the label be changed to "spice (sesame)" or "flavor (sesame)".[43] Via congressional act, it was declared that food manufacturers must acknowledge sesame as a priority food allergen by the 2023 deadline.[44]
Sneezing, body ache, headache (in rare cases, extremely painful cluster headaches may occur due to allergic sinusitis; these may leave a temporary time period of 1 and a half to 2 days with eye sensitivity), allergic conjunctivitis (includes watery, red, swelled, itchy, and irritating eyes), runny nose, irritation of the nose, nasal congestion, minor fatigue, chest pain and discomfort, coughing, sore throat, facial discomfort (feeling of stuffed face) due to allergic sinusitis, possible asthma attack, wheezing
Anaphylaxis, swelling, sometimes flatulence and vomiting
Egg yolk and egg white contain different proteins. An allergic individual may not have any reaction to consuming food only prepared with egg yolk and not egg white, or vice versa.[19] Due to high protein content, egg white allergy is more common than the reverse.[46] The majority of children with this allergy become tolerant by adulthood.[47]
Respiratory reactions, Anaphylaxis, oral allergy syndrome, sometimes vomiting
One of three allergies to seafood, not to be conflated with allergies to crustaceans and mollusks.[48] People with fish allergies have a 50% likelihood of being cross reactive with another fish species,[49] but some individuals are only allergic to one species, such as; tilapia[50] salmon,[48] or cod. A proper diagnosis is considered complicated due to these cross reactivity between fish species and other seafood allergies.[51] Hazard extends to exposure to cooking vapors or handling.[52]
Protein allergy,[53] not to be confused with lactose intolerance.[54] Allergy to cow's milk is the most common food allergy in infants and young children[46] but most outgrow the allergy in early childhood. Introducing baked cow's milk to allergic patients is associated with accelerated resolution of milk allergy.[55] Some evidence suggests goat's milk has less allergenic potential than cow's milk[56] and reduced risk of allergy development if infants are weaned with goat's milk.[57] Due to adult-onset sensitization it is estimated to be the second most common food allergy in American adults.[58]
Very rare allergies to chicken, turkey, squab, and sometimes more mildly to other avian meats.[59] Not to be confused with secondary reactions of bird-egg syndrome. The genuine allergy has no causal relationship with egg allergy, nor is there any close association with red meat allergy. Prevalence still unknown as of 2016.[60]
Allergies to the sugar carbohydrate found in beef, venison, lamb, and pork called alpha-gal. This carbohydrate is made by almost all mammals, with the notable exception of old world monkeys and apes (including humans). Tick bites may inject this substance into the bloodstream; combined with other defense mechanisms against tick bites, this causes the human body to flag alpha-gal as a foreign antigen.[63]
Shellfish allergies are highly cross reactive. Its prevalence is much higher than that of fish allergy. Shellfish allergy is the leading cause of food allergy in U.S adults.[58] As of 2018 six allergens have been identified to prawn alone; along with crab, it is the major culprit of seafood anaphylaxis.[48] In reference to it as one of the "Big 8"[64] or "major 14" allergens it is sometimes specified as a "crustacean shellfish" allergy, or more simply, a "crustacean allergy".[65][66] Sometimes it is conflated with an allergy to molluscan shellfish but complete tolerance to one but not the other is not uncommon. Most usually, a mono-sensitive individual will experience a crustacean allergy alone with tolerance to mollusks, rather than vice versa.[48]
The symptoms of an allergic reaction to molluscan shellfish should not be confused with the effects of shellfish poisoning which are a medical reactions that manifest after eating contaminated mollusks from certain areas of the world and lasts for several hours or days after onset.[67]
Cats express a number of protein allergens, numbered Fel d 1 to Fel d 7. Fel d 1 (from saliva, licked onto fur) and Fel d 4 are the most common culprits.
Dog
Routes
Inhalation
Symptoms
Rash, sneezing, congestion, wheezing, vomiting from coughing, Sometimes itchy welts.
Caused by dander, saliva or urine of dogs, or by dust, pollen or other allergens that have been carried on the fur.[69] Allergy to dogs is present in as much as 10 percent of the population.[69]
Burning, pain and swelling, possibly for days, swelling or blisters, vaginal redness,[70] fever, runny nose, extreme fatigue[71][72][73][74][75]
|In a case study in Switzerland, a woman who was allergic to Balsam of Peru was allergic to her boyfriend's semen following intercourse, after he drank large amounts of Coca-Cola.[76]
|A synthetic food dye used in processed foods like confections, soft drinks, flavoring syrups, condiments and convenience foods in order to create a potent yellow or bright green coloring. Prevalence of allergenicity is unclear but it is the most likely azo dye to cause hypersensitivity and reactions may occur from ingestion or skin contact. It is possible for some individuals to become desensitized. There is no strong evidence suggesting that tartrazine can cause hypersensitivity or intolerance in non-allergic individuals.
Many, including: severe headache, dizziness, blurred vision, fever, chills, body aches, flu symptoms, severe blistering, peeling, dark colored urine[79][80]
Although as many as 6–10% of the population are labelled as having a penicillin allergy, re-testing show that 90–95% of people labelled as such are actually not allergic. Re-testing and delabelling initiatives allow these patients to use penicillin instead of a higher-risk antibiotic.[87]
Cephalosporins
Routes
Oral, injection, skin contact
Symptoms
Maculopapular or morbilliform skin eruption, and less commonly urticaria, eosinophilia, serum-sickness–like reactions, and anaphylaxis.[88]
Rarer than penicillin allergy. Some cross-reaction due to molecular similarity.
The first broadly effective antibacterials to be used systemically. About 3% of the population are reported as allergic.[89]
Two regions of the sulfonamide antibiotic chemical structure are implicated in the hypersensitivity reactions associated with the class.
The first is the N1 heterocyclic ring, which causes a type I hypersensitivity (true allergy) reaction.
The second is the N4 amino nitrogen that, in a stereospecific process, forms reactive metabolites that cause either direct cytotoxicity or immunologic response.
The nonantibiotic sulfonamides lack both of these structures.[90]
Sulfites (also spelled "sulphites") are used as a preserving agents in many different foods, such as raisins, dried peaches, various other dried fruit, canned or frozen fruits and vegetables, wines, vinegars and processed meats. Allergy appears to be very rare in the general population but it is still often considered to be one of the top 10 food allergies.[25] It is debated whether reaction to sulfites is a true allergy.[93]
Water
Symptoms
Epidermal itching, swelling of the oral cavity after drinking water, anaphylaxis (in severe cases)[94][95][96][97][98]
↑Sharma A, Verma AK, Gupta RK, Dwivedi PD (August 2019). "A Comprehensive Review on Mustard-Induced Allergy and Implications for Human Health". Clinical Reviews in Allergy & Immunology. 57 (1): 39–54. doi:10.1007/s12016-017-8651-2. PMID29159565. S2CID38277555.
↑National Institutes of Health, NIAID Allergy Statistics "Food Allergy: Quick Facts". National Institute of Allergy and Infectious Diseases (NIAID). U.S. Department of Health and Human Services. Archived from the original on 2010-04-06. Retrieved 2011-12-18.
↑Savage JH, Matsui EC, Skripak JM, Wood RA (December 2007). "The natural history of egg allergy". The Journal of Allergy and Clinical Immunology. 120 (6): 1413–1417. doi:10.1016/j.jaci.2007.09.040. PMID18073126.
1234Ruethers T, Taki AC, Johnston EB, Nugraha R, Le TT, Kalic T, etal. (August 2018). "Seafood allergy: A comprehensive review of fish and shellfish allergens". Molecular Immunology. 100: 28–57. doi:10.1016/j.molimm.2018.04.008. PMID29858102.
↑Sicherer SH, Sampson HA (February 2010). "Food allergy". The Journal of Allergy and Clinical Immunology. 125 (2 Suppl 2): S116–S125. doi:10.1016/j.jaci.2009.08.028. PMID20042231.
↑National Institutes of Health, NIAID Allergy Statistics 2005 "Allergy Statistics". National Institute of Allergy and Infectious Diseases. Archived from the original on 7 February 2006.
↑Park YW (1 August 1994). "Hypo-allergenic and therapeutic significance of goat milk". Small Ruminant Research. 14 (2): 151–159. doi:10.1016/0921-4488(94)90105-8.
↑Zimerson E, Bruze M (2020). "Contact Allergy to Phenol-Formaldehyde Resins". In John S, Johansen J, Rustemeyer T, Elsner P, Maibach H (eds.). Kanerva's Occupational Dermatology (3rded.). Cham: Springer International Publishing. pp.789–798. doi:10.1007/978-3-319-68617-2_52. ISBN978-3-319-68617-2.
↑Kelkar PS, Li JT (September 2001). "Cephalosporin allergy". The New England Journal of Medicine. 345 (11): 804–809. doi:10.1056/NEJMra993637. PMID11556301.
↑Kaaber K, Veien NK, Tjell JC (February 1978). "Low nickel diet in the treatment of patients with chronic nickel dermatitis". The British Journal of Dermatology. 98 (2): 197–201. doi:10.1111/j.1365-2133.1978.tb01622.x. PMID629873. S2CID35632022.
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