What are the other Names of this Condition? (Also known as/Synonyms)

• Allergy to Food

What is Food Allergy? (Definition/Background Information)

• Food Allergy is a common condition that manifests as an abnormal immune reaction/response to certain foods in individuals who consume them. It is observed in both children and adults, more so in children
• Common food items that one may be allergic to include shellfish, peanut, soybean, tree nuts, and milk. Individuals may develop an allergic reaction on directly consuming the food item (whether raw or cooked), or through food-based products including oils, sauces, creams, or even medications 
• Food Allergy may occur immediately, or after a few hours following exposure. The exposure may be through food ingestion or from exposure to the specific food item in any other manner (such as inhalation of powder form or through skin contact). The condition may be mild, moderate, or severe
• Numerous signs and symptoms of the allergic reaction may be noted including runny nose, hives, sneezing, breathing difficulties, nausea and vomiting, and indigestion. In some individuals, Food Allergy may lead to an anaphylactic shock, which is a medical emergency
• Food Allergies are generally diagnosed using an antibody blood test, a skin-prick test, and an oral food challenge test. The diagnosis can also help identify food items that are to be avoided (in future)
• Anti-allergic medications form the first line of treatment for mild Food Allergies. However, in the case of a severe allergic reaction (anaphylaxis), epinephrine or adrenaline injections are recommended
• The prognosis of Food Allergy is generally good and most children overcome the condition during childhood, although some individuals have it lifelong. Awareness of such allergies and avoidance of specific foods that causes the allergy (via allergen-free foods) is the best form of prevention

Who gets Food Allergy? (Age and Sex Distribution)

• Food Allergies usually occur in infants and young children. However, the condition can occur in young and old adults too (any age group)
• According to studies, 1 in 17 children to about 1 in 25 adults may be allergic to one type of food or the other
• No gender preference is noted and both males and females are affected
• All racial and ethnic groups are equally vulnerable to the condition

What are the Risk Factors? (Predisposing Factors)

The common risk factors for Food Allergy include:

• Consuming food and food-based products in any form
• Any family history of an associated food allergy, or of asthma and hay fever
• Infants and young growing children are more at risk
• Having one form of (food) allergy puts one at risk for other forms

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Food Allergy? (Etiology)

An allergic reaction occurs in an individual with Food Allergy, because the immune system recognizes certain substances (such as proteins) in food as being dangerous and harmful to the body.

• Intake of the food (protein) results in the production of antibodies, specifically immunoglobulin E (IgE). The next time the individual is exposed to the particular food, the antibodies that are circulating in blood causes an antibody-antigen reaction
• However, Food Allergy can be IgE mediated or non-IgE mediated. Due to this, the set of symptoms observed and their period of onset may vary. In some cases, it may be diagnostically challenging too
• The antibody-antigen reaction results in the production of histamine and other chemical messengers, which cause the symptoms seen during an allergic reaction
• Young children are more prone to the condition, mostly due to an under-developed digestive system
• The quantity of food that triggers an allergy may not be significantly large. Sometimes, consuming tiny amounts of the food (allergen) is sufficient to trigger Food Allergy

In some cases, a severe allergic reaction termed as anaphylaxis may occur, which is a medical emergency that requires immediate medical attention.

What are the Signs and Symptoms of Food Allergy?

The signs and symptoms of Food Allergy may start to appear within a few minutes, to a couple of hours, after the individual has consumed the substance. In some, the symptoms are mild, while in others they are severe. It also depends on the specific food type causing the condition. A severe allergic reaction is a medical emergency.

The common signs and symptoms of Food Allergy may include:

• Itching of skin
• Urticaria (hives), skin rashes, or eczema
• Coughing, sneezing
• Shortness of breath (trouble breathing), wheezing, asthma-like symptoms
• Runny or stuffy nose
• Watery eyes, redness, and irritation
• Nausea and vomiting
• Diarrhea
• Abdominal distention (bloating)

Generally, not all episodes of allergy will be of the same severity. In some individuals, the most severe symptom caused by certain Food Allergies is anaphylaxis.

• Anaphylaxis (sometimes called an anaphylactic shock) is a life-threatening, whole-body allergic reaction
• During anaphylaxis, tissues in various body parts release histamine and other messenger chemicals, which causes swelling of the throat and other symptoms
• Swelling of the throat is especially dangerous as this can cause shortness of breath. If the swelling is not reduced soon, then there is a possibility that the individual could die from a lack of sufficient oxygen
• It can also result in a bluish skin, weak pulse, and decreased blood pressure (hypotension)

How is Food Allergy Diagnosed?

The diagnosis of Food Allergy may involve the following:

• Physical examination, assessment of symptoms, and medical history evaluation (history of allergies in the family)
• Food diary: Once an allergy is suspected, the healthcare provider may request to maintain a food diary, to note what is being consumed on a regular basis and the corresponding symptoms observed. The healthcare provider can help check which food products are causing allergy, through a process of elimination

The tests that are usually conducted to diagnose Food Allergy include:

• Oral food challenge testing; when the individual is administered the allergens in a controlled manner to check for symptoms that develop
• Radioallergosorbent (RAS) test; to determine the specific allergy-causing substance
• Skin-prick test:
  • For this test, tiny amounts of certain substances are injected right underneath the skin (forearm, upper arm, or back)
  • After 15-20 minutes, if the spot where the chemical was injected swells, or if there is redness noticed, then this indicates that the individual may be allergic to the substance
• Blood test to detect antibodies (IgE antibody test)

Note: Do-it-yourself allergy testing kits that are commercially available are usually not recommended by healthcare providers.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Food Allergy?

The complication of Food Allergy is associated with the allergic reaction itself and it depends on the severity of the reaction. It may include:

• Anaphylactic shock/reaction that may be life-threatening
• Having one form of allergy can make the individual prone to other allergy types
• In severe reactions, a tracheostomy may have to be performed during an emergency situation

How is Food Allergy Treated?

The treatment of Food Allergy may be undertaken in the following manner:

• Avoiding consumption of foods containing the specific allergy-inducing product; elimination diets supervised by a qualified dietitian
• Anti-allergic medication for mild reactions; antihistamine therapy, that is prescribed by the allergy physician
• Symptomatic treatment; use of decongestants, especially for nose block including steroid sprays
• In the case of anaphylaxis (severe allergic reaction), epinephrine or adrenaline is immediately administered
• Breathing support as necessary, control asthma symptoms and low blood pressure
• Immunotherapy, in case of severe allergies, for long-term tolerance development

Provide psychological support to children with Food Allergies.

How can Food Allergy be Prevented?

The best way to prevent Food Allergy is to avoid the specific food item that the individual is allergic to. Additionally, the following factors may be considered:

• Check ingredients of food before using; educate oneself on foods that potentially contain the allergic substance
• Parents must be watchful and read food labels, to ensure they do not inadvertently give their child such foods
• Studies have shown that breastfeeding children for 4-6 months or over, can help build their body immunity and make them less prone to allergies
• Appropriate maternal diet during pregnancy can help build stronger resistance (against allergies) in children
• Washing hands with soap and water, in case of contact with an allergen, especially before eating
• Avoiding contaminating food items during food preparation; use separate food utensils for preparing allergy-free meals, when possible
• Use alternatives, where possible
• While eating out, explain your food allergy to hotel/restaurant service staff and ensure that your food is without the substances you are allergic to
• In hotels and restaurants, separating the preparation of potential food allergens (such as milk, peanuts, tree nuts, soy, fish) from general food preparation counters may be beneficial to individuals with food allergies. This can help avoid cross-contact (allergens getting transferred from one food type to another)
• Generating public awareness on various food allergies
• It is important to note that cooking to high-flame or cooking to recommended standards will NOT ensure elimination of the allergen

In case the child or adult is susceptible to an anaphylactic shock (high-risk individuals) from Food Allergy, the following should be considered:

• Being watchful of triggers and avoiding them
• Wearing medical alert information bracelets or suitable devices
• Carry auto-injector epinephrine or adrenaline medications such as EpiPen, Anapen, or Twinject. Since the condition may recur, it is advised to carry 2 doses (2 pens)
• Supervise children on how to self-administer the injection, if required
• If child is prone to anaphylactic reaction, then information (preferably written instructions) should be given to day care, school authorities accordingly
• Adults should inform their spouses, colleagues, and friends, about the condition, in case of a future emergency

Presently, in many countries, due to labeling and consumer protection laws, foods have suitable labels that indicate their content.

What is the Prognosis of Food Allergy? (Outcomes/Resolutions)

• The prognosis of Food Allergy depends on the severity of the signs and symptoms, but it is generally good. Most cases resolve during early childhood
• Some individuals may have it for the rest of their lives, but are able to cope well with modified diets that exclude the specific food type
• In some cases, the allergic reaction may be severe, causing anaphylaxis. This is a medical emergency that can lead to a respiratory failure. It requires an immediate treatment of the condition. In such cases, the prognosis is guarded and it depends on whether immediate medical assistance is provided

Additional and Relevant Useful Information for Food Allergy:

Sometimes, non-food items (such as cosmetics, hair care products, topical applications, medications, etc.) containing the specific food item or food derivatives may cause allergies too.