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

• Allergy to Soybeans
• Soya Allergy

What is Soy Allergy? (Definition/Background Information)

• Soy Allergy (or Soya Allergy) is a relatively common condition that manifests as an abnormal immune reaction/response to certain products of the soybean plant, in individuals who consume them
• The soybean (or Glycine max) is a leguminous plant that produces edible beans, which is used in food preparation and products. Soybean oil is also derived from the plant. The plant is mostly grow in USA and certain south American countries
• Soybean food products are found in soy meal (meal maker), soy sauce, soy milk and flour, tofu, protein food products (textured vegetable protein or TVP), whey, soy (vegetable) oil, seasoning paste, and sprouts. It is also found in ice creams, cheese, and yogurt, foods containing lecithin, and many canned foods
• Soy proteins are not as potent allergens as say, wheat or other food protein allergens. For these and many other reasons, soy milk is used as an alternative to breastfeed milk in infants who are allergic to it. Also, several soy-based formulae are available for infants
• Soy Allergy may occur immediately, or after a few hours following exposure. The exposure is normally through food ingestion. The condition affects infants, children, and adults. The allergy may be grouped based on the soy food product used, such as:
  • Soy Milk Allergy
  • Soy Lecithin Allergy
  • Soy Sauce Allergy
• Numerous signs and symptoms of the allergic reaction may be noted including runny nose, hives, conjunctivitis, breathing difficulties, nausea and vomiting, and indigestion. In some rare cases, Soy Allergy may lead to an anaphylactic shock, which is a medical emergency
• Such 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 soy-based food items that are to be avoided (in future)
• Anti-allergic medications form the first line of treatment for mild Soy Allergies. However, in the case of a severe allergic reaction (anaphylaxis), epinephrine or adrenaline injections are recommended
• The prognosis of Soy Allergy is generally good and many overcome the condition during childhood, although in some individuals it may be present 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 Soy Allergy? (Age and Sex Distribution)

• Soy Allergies can occur in infants, young and old children, including in adults
• No gender preference is noted and both males and females are affected
• All racial and ethnic groups are equally vulnerable to the condition; however, some countries report more cases of Soy Allergy (such as USA)

What are the Risk Factors for Soy Allergy? (Predisposing Factors)

The risk factors for Soy Allergy may include:

• Consuming soy products and soy-based food preparations
• Any family history of an associated food allergy
• 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 Soy Allergy? (Etiology)

An allergic reaction occurs in an individual with Soy Allergy, because the immune system recognizes certain compounds (proteins) in soy foods as being dangerous and harmful to the body. Soy contains certain proteins that induce allergy; about 15 proteins have been identified as potential allergens.

• Intake of soy results in the production of antibodies, specifically immunoglobulin E (IgE). The next time the individual is exposed to the same compound, the antibodies that are circulating in blood causes an antibody-antigen reaction
• The antibody-antigen reaction results in the production of histamine and other chemical messengers, which cause the symptoms seen during an allergic reaction. However, Soy Allergy can be IgE mediated or non-IgE mediated
• 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 allergen (soy foods) is sufficient to trigger Soy Allergy
• Non-food items using soy based preparations may also cause allergy symptoms

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 Soy Allergy?

The signs and symptoms of Soy Allergy may start to appear within a few minutes, to a couple of hours, after the individual has consumed soy-based food products. The symptoms are also common to other types of food allergies. In some, the symptoms are mild, while in others they are severe. In many cases, systemic signs and symptoms may be noted.

The signs and symptoms of Soy Allergy may include:

• Itching of skin
• Urticaria (hives) and angioedema (swelling of the tissues due to fluid accumulation)
• Coughing, sneezing
• Shortness of breath (trouble breathing), wheezing, asthma-like symptoms
• Conjunctivitis causing watery eyes, redness, and itching sensation
• Runny or stuffy nose
• Nausea and vomiting
• Diarrhea
• Abdominal distention (bloating) and pain

Generally, not all episodes of allergy will be of the same severity. In some individuals, the most severe symptom caused is anaphylaxis; however, anaphylaxis occurs rarely due to Soy Allergy.

• 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 Soy Allergy Diagnosed?

The diagnosis of Soy 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 soy products are causing allergy, through a process of elimination

The tests that are usually conducted to diagnose Soy 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 (allergy) 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 (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 Soy Allergy?

The complication of Soy 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
• Soy based foods can also cause food intolerance
• In severe reactions, a tracheostomy may have to be performed during an emergency situation

How is Soy Allergy Treated?

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

• Avoiding consumption of foods containing soybean products; 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 such food allergies.

How can Soy Allergy be Prevented?

The best way to prevent Soy Allergy is to avoid soy products 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 soy products
• Parents must be watchful and read food labels, to ensure they do not inadvertently give their child sesame-containing 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 to soy products, 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 soy, tree nuts, milk, 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 Soy 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 Soy Allergy? (Outcomes/Resolutions)

• The prognosis of Soy Allergy depends on the severity of the signs and symptoms, but it is generally good with suitable treatment. Many cases are known to resolve during early childhood itself
• Some individuals may have it for the rest of their lives, but are able to cope well with modified diets that exclude soy products
• 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 Soy Allergy:

• Allergy to one legume (soybean), may not necessarily mean allergy to another legume, such as lentils, peanuts/groundnuts, etc.
• 95% of all soybean (meal) plant produce is used for farm animal products or livestock feed