When eggs are introduced to a baby's diet is thought to affect risk of developing allergy, but there are contradictory recommendations. A 2016 review acknowledged that introducing peanuts early appears to have a benefit, but stated "The effect of early introduction of egg on egg allergy are controversial." A meta-analysis published the same year supported the theory that early introduction of eggs into an infant's diet lowers risk, and a review of allergens in general stated that introducing solid foods at 4–6 months may result in the lowest subsequent allergy risk. However, an older consensus document from the American College of Allergy, Asthma and Immunology recommended that introduction of chicken eggs be delayed to 24 months of age.

Breastfeeding for more than four months may prevent atopic dermatitis, cow's milk allergy, and wheezing in early childhood. Early exposure to potential allergens may be protective. Specifically, early exposure to eggs and peanuts reduces the risk of allergies to these.

To avoid an allergic reaction, a strict diet can be followed. It is difficult to determine the amount of allergenic food required to elicit a reaction, so complete avoidance should be attempted. In some cases, hypersensitive reactions can be triggered by exposures to allergens through skin contact, inhalation, kissing, participation in sports, blood transfusions, cosmetics, and alcohol.

There is active research on trying oral immunotherapy (OIT) to desensitize people to egg allergens. A Cochrane Review concluded that OIT can desensitize people, but it remains unclear whether long-term tolerance develops after treatment ceases, and 69% of the people enrolled in the trials had adverse effects. They concluded there was a need for standardized protocols and guidelines prior to incorporating OIT into clinical practice. A second review noted that allergic reactions, up to anaphylaxis, can occur during OIT, and recommends this treatment not be routine medical practice. A third review limited its scope to trials of baked egg-containing goods such as bread or cake as a means of resolving egg allergy. Again, there were some successes, but also some severe allergic reactions, and the authors came down on the side of not recommending this as treatment.

Two reviews on avoiding common allergy-inducing foods during pregnancy or lactation concluded that there is no strong evidence to recommend changes to the diets of pregnant or nursing women as a means of preventing the development of food allergy in their infants. For mothers of infants considered at high risk of developing cow's milk allergy because of a family history, there is some evidence that the nursing mother avoiding allergens may reduce risk of the child developing eczema, but the Cochrane review concluded that more research is needed.

Guidelines from various government and international organizations recommend that for the lowest allergy risk, infants be exclusively breastfed for 4-6 months. There does not appear to be any benefit to extending that period beyond six months. If a nursing mother decides to start feeding with an infant formula prior to four months the recommendation is to use a formula containing cow's milk proteins.

A different consideration occurs when there is a family history - parent or older siblings - of milk allergy. In this situation there are recommendations to avoid formula that contains intact cow's milk proteins. Options are substituting a product containing extensively hydrolyzed protein, or non-dairy protein, or free amino acids. The hydrolyzing process breaks intact proteins into fragments, in theory reducing allergenic potential. In 2006 the U.S. Food and Drug Administration (FDA) rejected a health claim proposed by Nestle that a formula based on partially hydrolyzed whey protein would reduce risk of developing allergy. Ten years later the FDA reconsidered and allowed a health claim, with the caveat that the claim include wording to the effect that the scientific evidence was weak at best. A meta-analysis published the same year disputed this, concluding that based on dozens of clinical trials there was no evidence to support a claim that a partially hydrolyzed formula could reduce the risk of eczema.

Once an infant has demonstrated milk allergy symptoms to a formula containing intact cow's milk proteins, a dairy-based hydrolyzed formula is not appropriate. Soy formula is a common substitution, but infants with milk allergy may have an allergic response to soy formula. Hydrolyzed rice formula is an option, as are the more expensive amino acid-based formulas.

The need for a dairy-free diet should be reevaluated every six months by testing milk-containing products low on the "milk ladder", such as fully cooked, i.e., baked foods containing milk, in which the milk proteins have been denatured, and ending with fresh cheese and milk. Desensitization via oral immunotherapy holds some promise but is still being actively researched (see Research).

Treatment for accidental ingestion of milk products by allergic individuals varies depending on the sensitivity of the person. An antihistamine such as diphenhydramine (Benadryl) 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, i.e., an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. A second dose is needed in 16-35% of episodes.

The mainstay of treatment for food allergy is total avoidance of the foods identified as allergens. An allergen can enter the body by consuming a food containing the allergen, and can also be ingested by touching any surfaces that may have come into contact with the allergen, then touching the eyes or nose. For people who are extremely sensitive, avoidance includes avoiding touching or inhaling the problematic food.

If the food is accidentally ingested and a systemic reaction (anaphylaxis) occurs, then epinephrine should be used. A second dose of epinephrine may be required for severe reactions. The person should then be transported to the emergency room, where additional treatment can be given. Other treatments include antihistamines and steroids.

Some foods during pregnancy has been linked to allergies in the child. Vegetable oil, nuts and fast food may increase the risk while fruits, vegetables and fish may decrease it. Another review found no effect of eating fish during pregnancy on allergy risk.

Probiotic supplements taken during pregnancy or infancy may help to prevent atopic dermatitis.

Peanut allergies tend to resolve in childhood less often than allergies to soy, milk, egg, and wheat. Accordingly, re-evaluation of peanut allergy is recommended on a yearly basis for young children with favorable previous test results, and every few years or longer for older children and adults.

The Synthetic epitope vaccine is an in-development vaccine to provide a long term vaccine for allergies.

Allergens that are airborne survive for months or even years by themselves, hence removing anything that can trap and hold the allergens (carpet, rugs, pillows) and cleaning regularly and thoroughly with HEPA filters and electrostatic air purifier systems reduces risk. Frequent hand washing, especially after handling the cat, and washing hands prior to touching eyes, nose, or mouth, and limiting the cat's access to certain rooms, such as the bedroom or other rooms where much time is spent, may also reduce allergic reactions.

Treatment for accidental ingestion of soy products by allergic individuals varies depending on the sensitivity of the person. An antihistamine such as diphenhydramine (Benadryl) 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, i.e., an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. A second dose is needed in 16-35% of episodes.

Peanut allergy may be preventable by feeding babies who are at high risk foods that contain peanuts when they are as young as four to six months of age.

Management of wheat allergy consists of complete withdrawal of any food containing wheat and other gluten-containing cereals (gluten-free diet). Nevertheless, some patients can tolerate barley, rye or oats.

In people suffering less severe forms of wheat-dependent exercise induced anaphylaxis (WDEIA), may be enough completely avoiding wheat consumption before exercise and other cofactors that trigger disease symptoms, such as nonsteroidal anti-inflammatory drugs and alcohol.

Wheat is often a cryptic contaminant of many foods; more obvious items are bread crumbs, maltodextrin, bran, cereal extract, couscous, cracker meal, enriched flour, gluten, high-gluten flour, high-protein flour, seitan, semolina wheat, vital gluten, wheat bran, wheat germ, wheat gluten, wheat malt, wheat starch or whole wheat flour. Less obvious sources of wheat could be gelatinized starch, hydrolyzed vegetable protein, modified food starch, modified starch, natural flavoring, soy sauce, soy bean paste, hoisin sauce, starch, vegetable gum, specifically Beta-glucan, vegetable starch.

For those allergic to fruits, cooking may help reduce or eliminate the reaction to some fruits.

People with this allergy might not necessarily be allergic to citrus fruits.

Management of allergies typically involves avoiding what triggers the allergy and medications to improve the symptoms. Allergen immunotherapy may be useful for some types of allergies.

Triticeae gluten-free oats (free of wheat, rye or barley) may be a useful source of cereal fiber. Some wheat allergies allow the use of rye bread as a substitute. Rice flour is a commonly used alternative for those allergic to wheat. Wheat-free millet flour, buckwheat, flax seed meal, corn meal, quinoa flour, chia seed flour, tapioca starch or flour, and others can be used as substitutes.

Some symptoms might weaken if people get allergy shots. After getting several treatments for a long time, some allergic people will not have reactions afterwards.

Some reactions have been eased by replacing original rice with genetically modified rice. This is regarded as a new choice for rice allergic people.

Reactions might lessen by staying away from rice long-term.

Prevention involves an exclusion diet and vigilant avoidance of foods that may be contaminated with tree nuts, nut particles, or oils extracted from nuts. In the United States, the federal Food Allergen Labeling and Consumer Protection Act (FALCPA) requires that any packaged food product that contains tree nuts as an ingredient must list the specific tree nut on the label. Foods that almost always contain tree nuts include pesto, marzipan, Nutella, baklava, pralines, nougat, gianduja, and turrón. Other common foods that may contain tree nuts include cereals, crackers, cookies, baked goods, candy, chocolates, energy/granola bars, flavored coffee, frozen desserts, marinades, barbecue sauces, and some cold cuts, such as mortadella. Tree nut oils (especially shea nut) are also sometimes used in lotions and soaps. Asian and African restaurants, ice cream parlors, and bakeries are considered high-risk for people with tree nut allergy due to the common use of nuts and the possibility of cross contamination.

OAS must be managed in conjunction with the patient's other allergies, primarily the allergy to pollen. The symptom severity may wax and wane with the pollen levels. Published pollen counts and seasonal charts are useful but may be ineffective in cases of high wind or unusual weather, as pollen can travel hundreds of kilometers from other areas.

In addition, patients are advised to avoid the triggering foods, particularly nuts.

Peeling or cooking the foods has been shown to eliminate the effects of some allergens such as "mal d 1" (apple), but not others such as celery or strawberry. In the case of foods such as hazelnut, which have more than one allergen, cooking may eliminate one allergen but not the other.

Antihistamines may also relieve the symptoms of the allergy by blocking the immune pathway. Persons with a history of severe anaphylactic reaction may carry an injectable emergency dose of epinephrine (such as an EpiPen). Oral steroids may also be helpful. Allergy immunotherapy has been reported to improve or cure OAS in some patients. Immunotherapy with extracts containing birch pollen may benefit OAS sufferers of apple or hazelnut related to birch pollen-allergens. Even so, the increase in the amount of apple/hazelnut tolerated was small (from 12.6 to 32.6 g apple), and as a result, a patient's management of OAS would be limited.

For some people, the sensitivity is so extreme that replacement of latex products with products made from alternative materials may still result in a reaction if the products are manufactured in the same facility as the latex-containing products, due to trace quantities of natural rubber latex on the non-latex products.

Alpha-gal allergies develop after a person has been bitten by the lone star tick in the United States, the European castor bean tick, and the paralysis tick in Australia. Alpha-gal is not naturally present in apes and humans, but is in all other mammals. If a tick feeds on another mammal, the alpha-gal will remain in its alimentary tract. The tick will then inject the alpha-gal into a person's skin, which in turn will cause the immune system to release a flood of IgE antibodies to fight off the foreign carbohydrate. Researchers still do not know which specific component of tick saliva causes the reaction.

A 2012 preliminary study found unexpectedly high rates of alpha-gal allergies in the Western and North Central parts of the United States, which suggests that the allergy may be spread by unknown tick species. Examples of alpha-gal allergies were even present in Hawaii, where none of the ticks identified with the allergies live. Human factors were suggested but no specific examples were provided.

Alpha-gal is present in the anti-cancer drug cetuximab, as well as the IV fluid replacements Gelofusine and Haemaccel. Blood thinners derived from porcine intestine and replacement heart valves derived from porcine tissue may also contain alpha-gal.

There has been at least one instance of a man with an alpha-gal allergy going into anaphylaxis after receiving a heart valve transplant. Some researchers have suggested that the alpha-gal which is prevalent in pig's tissue and used for xenografts may contribute to organ rejection.

The allergy was first formally identified as originating from tick bites in 2002 by Thomas Platts-Mills. Platts-Mills and Scott Commins were attempting to discover why some people were reacting negatively to the carbohydrate in the cancer drug cetuximab. They had previously hypothesized that a fungal infection or parasite could lead to the allergy. It wasn't until Platts-Mills was bitten by a tick and developed alpha-gal allergies that his team also came to the conclusion that there was a link between tick bites and the allergy. They found that the IgE antibody response to the mammalian oligosaccharide epitope, alpha-gal, was associated with both the immediate-onset anaphylaxis during first exposure to intravenous cetuximab and the delayed-onset anaphylaxis 3 to 6 hours after ingestion of mammalian food products, such as beef or pork.

Alpha-gal allergies are very similar to pork–cat syndrome and hence misidentification can occur. Pork–cat syndrome usually elicits an immediate allergic response, while a true alpha-gal allergy typically features a delayed allergic reaction of 3 to 8 hours after ingestion of the allergen.

Allergies to a specific pollen are usually associated with OAS reactions to other certain foods. For instance, an allergy to ragweed is associated with OAS reactions to banana, watermelon, cantaloupe, honeydew, zucchini, and cucumber. This does not mean that all sufferers of an allergy to ragweed will experience adverse effects from all or even any of these foods. Reactions may be associated with one type of food, with new reactions to other foods developing later. However, reaction to one or more foods in any given category does not necessarily mean a person is allergic to all foods in that group.

Avoiding allergens will help prevent symptoms. Allergies that a child has to the family pet can be controlled by removing the animal and finding it a new home. Exterminating cockroaches, mice and rats and a thorough cleaning can reduce symptoms of an allergy in children. Dust mites are attracted to moisture. They consume human skin that has come off and lodged in, furniture, rugs, mattresses, box springs, and pillows. The child's bedding can be covered with allergen-proof covers. Laundering of the child's clothing, bed linens and blankets will also reduce exposure.

Exposure to allergens outside the home can be controlled with the use of air conditioners. Washing the hair, taking a bath or shower before bedtime can be done to remove allergens that have been picked up from outside the home. If grass or grass pollen is an allergen it is sometimes beneficial to remain indoors while grass is being cut or mowed. Children with allergies to grass can avoid playing in the grass to prevent allergic symptoms. Staying out of piled leaves in the fall can help. Pets returning into the home after being outdoors may track in allergens.

Risk factors for drug allergies can be attributed to the drug itself or the characteristics of the patient. Drug-specific risk factors include the dose, route of administration, duration of treatment, repetitive exposure to the drug, and concurrent illnesses. Host risk factors include age, sex, atopy, specific genetic polymorphisms, and inherent predisposition to react to multiple unrelated drugs (multiple drug allergy syndrome).

A drug allergy is more likely to develop with large doses and extended exposure.