What food can cause skin allergy
There’s another type of food allergy known as a non-IgE-mediated food allergy, caused by diverse cells in the immune system.
This is much harder to diagnose as there’s no test to accurately confirm non-IgE-mediated food allergy.
This type of reaction is largely confined to the skin and digestive system, causing symptoms such as heartburn, indigestion and eczema.
In babies, a non-IgE-mediated food allergy can also cause diarrhoea and reflux, where stomach acid leaks up into the throat.
It’s rare for someone to have an allergic reaction to food additives.
However, certain additives may cause a flare-up of symptoms in people with pre-existing conditions.
Sulphur dioxide (E) and other sulphites (from numbers E to E) are used as preservatives in a wide range of foods, especially soft drinks, sausages, burgers, and dried fruits and vegetables.
Sulphur dioxide is produced naturally when wine and beer are made, and is sometimes added to wine. Anyone who has asthma or allergic rhinitis may react to inhaling sulphur dioxide.
A few people with asthma own had an attack after drinking acidic drinks containing sulphites, but this isn’t thought to be extremely common.
Food labelling rules require pre-packed food sold in the UK, and the relax of the European Union, to show clearly on the label if it contains sulphur dioxide or sulphites at levels above 10mg per kg or per litre.
Benzoic acid (E) and other benzoates (E to E, E and E) are used as food preservatives to prevent yeasts and moulds growing, most commonly in soft drinks. They happen naturally in fruit and honey.
Benzoates could make the symptoms of asthma and eczema worse in children who already own these conditions.
Sheet final reviewed: 15 April
Next review due: 15 April
|Hives on the back are a common allergy symptom.|
|Symptoms||Itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, low blood pressure|
|Usual onset||Minutes to several hours of exposure|
|Duration||Long term, some may resolve|
|Causes||Immune response to food|
|Risk factors||Family history, vitamin D deficiency, obesity, high levels of cleanliness|
|Diagnostic method||Based on a medical history, elimination diet, skin prick test, oral food challenge|
|Differential diagnosis||Food intolerance, celiac disease, food poisoning|
|Prevention||Early exposure to potential allergens|
|Treatment||Avoiding the food in question, having a plan if exposure occurs, medical alert jewelry|
|Frequency||~6% (developed world)|
A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. This typically occurs within minutes to several hours of exposure. When the symptoms are severe, it is known as anaphylaxis. A food intolerance and food poisoning are separate conditions, not due to an immune response.
Common foods involved include cow’s milk, peanuts, eggs, shellfish, fish, tree nuts, soy, wheat, rice, and fruit. The common allergies vary depending on the country. Risk factors include a family history of allergies, vitamin D deficiency, obesity, and high levels of cleanliness. Allergies happen when immunoglobulin E (IgE), part of the body’s immune system, binds to food molecules. A protein in the food is generally the problem. This triggers the release of inflammatory chemicals such as histamine. Diagnosis is generally based on a medical history, elimination diet, skin prick test, blood tests for food-specific IgE antibodies, or oral food challenge.
Early exposure to potential allergens may be protective. Management primarily involves avoiding the food in question and having a plan if exposure occurs. This plan may include giving adrenaline (epinephrine) and wearing medical alert jewelry. The benefits of allergen immunotherapy for food allergies is unclear, thus is not recommended as of [update]. Some types of food allergies among children resolve with age, including that to milk, eggs, and soy; while others such as to nuts and shellfish typically do not.
In the developed world, about 4% to 8% of people own at least one food allergy. They are more common in children than adults and appear to be increasing in frequency. Male children appear to be more commonly affected than females. Some allergies more commonly develop early in life, while others typically develop in later life. In developed countries, a large proportion of people believe they own food allergies when they actually do not own them. The declaration of the presence of trace amounts of allergens in foods is mandatory only in Brazil.
In children, the foods that most commonly cause an allergic reaction are:
- milk – if a kid has an allergy to cows’ milk, they’re probably allergic to every types of milk, as well as infants’ and follow-on formula
In adults, the foods that most commonly cause an allergic reaction are:
- tree nuts – such as walnuts, brazil nuts, almonds and pistachios
- shellfish – such as crab, lobster and prawns
However, any type of food can potentially cause an allergy.
Some people own allergic reactions to:
- fruit and vegetables – these generally only cause symptoms affecting the mouth, lips and throat (oral allergy syndrome)
- celery or celeriac – this can sometimes cause anaphylactic shock
- sesame seeds
- pine nuts (a type of seed)
- gluten – a type of protein found in cereals
- meat – some people are allergic to just one type of meat, while others are allergic to a range of meats; a common symptom is skin irritation
Signs and symptoms
Food allergies generally own a quick onset (from seconds to one hour) and may include:
- Diarrhea, abdominal pain, and/or stomach cramps
- Runny or congested nose
- Wheezing and/or shortness of breath
- Swelling (angioedema) of lips, tongue, eyelids, or the whole face
- Difficulty swallowing
- Hoarse voice
- Itching of mouth, lips, tongue, throat, eyes, skin, or other areas
In some cases, however, onset of symptoms may be delayed for hours.
Symptoms can vary.
The quantity of food needed to trigger a reaction also varies.
Serious harm regarding allergies can start when the respiratory tract or blood circulation is affected.
The previous can be indicated through wheezing and cyanosis. Poor blood circulation leads to a feeble pulse, pale skin and fainting.
A severe case of an allergic reaction, caused by symptoms affecting the respiratory tract and blood circulation, is called anaphylaxis.
When symptoms are related to a drop in blood pressure, the person is said to be in anaphylactic shock. Anaphylaxis occurs when IgE antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show symptoms. Those with asthma or an allergy to peanuts, tree nuts, or seafood are at greater risk for anaphylaxis.
Who’s at risk?
Exactly what causes the immune system to error harmless proteins as a threat is unclear but some things are thought to increase your risk of a food allergy.
If you own a parent, brother or sister with an allergic condition – such as asthma, eczema or a food allergy – you own a slightly higher risk of developing a food allergy.
However, you may not develop the same food allergy as your family members.
Other allergic conditions
Children who have atopic dermatitis (eczema) in early life are more likely to develop a food allergy.
The immune system
The immune system protects the body by producing specialised proteins called antibodies.
Antibodies identify potential threats to your body, such as bacteria and viruses. They signal your immune system to release chemicals to kill the threat and prevent the spread of infection.
In the most common type of food allergy, an antibody known as immunoglobulin E (IgE) mistakenly targets a certain protein found in food as a threat. IgE can cause several chemicals to be released, the most significant being histamine.
Histamine causes most of the typical symptoms that happen during an allergic reaction.
For example, histamine:
- affects nerves in the skin, causing itchiness
- causes little blood vessels to expand and the surrounding skin to become red and swell up
- increases the quantity of mucus produced in your nose lining, which causes itching and a burning sensation
In most food allergies, the release of histamine is limited to certain parts of the body, such as your mouth, throat or skin.
In anaphylaxis, the immune system goes into overdrive and releases large amounts of histamine and numerous other chemicals into your blood.
This causes the wide range of symptoms associated with anaphylaxis.
The rise in food allergy cases
The number of people with food allergies has risen sharply over the past few decades and, although the reason is unclear, other allergic conditions such as atopic dermatitis own also increased.
One theory behind the rise is that a typical child’s diet has changed considerably over the final 30 to 40 years.
Another theory is that children are increasingly growing up in «germ-free» environments.
This means their immune systems may not get sufficient early exposure to the germs needed to develop properly.
This is known as the hygiene hypothesis.