Food allergy

Sometimes, our bodies react to certain foods.

This happens because the body thinks the food is bad. It tries to fight the food to stay safe.

This can make a person feel itchy. They might get a red rash or a swollen face. Some people may even have trouble breathing.

Common foods that cause this are milk and eggs. Peanuts and tree nuts are also common. Some people react to fish or shellfish too.

Many children grow out of these allergies as they get older. But for some, it lasts a long time. It is important to check food labels.

Knowing what is in food keeps us safe and healthy.

A food allergy is an abnormal response by the immune system. The immune system is the part of the body that fights germs.

Sometimes, the body thinks a safe food is a threat. This happens when IgE antibodies, which are tiny markers, find proteins in food. These markers tell the body to act. The body then lets out chemicals like histamine.

This can cause many symptoms. A person might feel itchy or get a rash. They may also have a swollen tongue or trouble breathing. If the reaction is very severe, it is called anaphylaxis.

Common foods that cause allergies include milk, eggs, peanuts, and wheat. In the US, sesame is also a major one. Many children outgrow allergies to milk or eggs. However, allergies to nuts or shellfish often last a lifetime.

People can manage allergies by avoiding certain foods. They might also carry an epinephrine autoinjector. This is a tool that gives medicine to help during a reaction.

Doctors can find allergies using skin prick tests.

They may also use blood tests.

A food allergy is an abnormal response from your immune system. Usually, your immune system protects you from germs and sickness. However, with an allergy, the body thinks a safe food is a threat. This can lead to many different symptoms. Some people feel itchy or get a red rash called hives. Others might have a swollen tongue or trouble breathing. If a reaction is very severe, it is called anaphylaxis.

This reaction happens through a specific way it works in the body. It starts when your immune system makes things called IgE antibodies. These antibodies look for specific proteins in the food you eat. When they find these proteins, they bind to them like a tiny tag. This tells the body to release chemicals like histamine. Histamine is what often causes the itchy feeling.

Doctors use several ways to find out if someone has an allergy. They might look at a person's medical history first. They can also use a skin prick test to see how the skin reacts. Another way is through blood tests that look for those IgE antibodies. Sometimes, a doctor might even use an oral food challenge. This is a way to see if food causes a reaction in a safe setting.

Many different foods can cause these reactions. In the United States, there are nine foods that must be listed on labels. These include milk, eggs, peanuts, tree nuts, fish, shellfish, soy, wheat, and sesame. The law for sesame was updated when President Biden signed the FASTER Act in April 2021. Peanuts are very common and can cause severe reactions. About 2% of people in the Western world have a peanut allergy.

Managing a food allergy means staying safe every day. The best way is to avoid the food that causes the problem. People must also watch out for cross-contact. This happens when a tiny bit of an allergen moves to a safe food. This can happen through shared tools or surfaces in a kitchen. Many people also carry an epinephrine autoinjector. This tool gives medicine to help if a person has a bad reaction.

A food allergy is an abnormal immune response to certain foods. Usually, the immune system protects the body from harmful pathogens like viruses. In a person with an allergy, the immune system mistakenly identifies harmless food proteins as threats. This reaction can cause symptoms ranging from mild itchiness to life-threatening emergencies. In the developed world, approximately 4% to 8% of people have at least one food allergy. These conditions are more common in children than in adults, and their frequency appears to be increasing.

The biological mechanism of a food allergy involves specific proteins and antibodies. When a person is exposed to an allergen, their immune system may produce immunoglobulin E, or IgE. These IgE antibodies act as markers by binding to specific molecules in the food. This process is known as allergic sensitization. Once the IgE antibodies bind to the food proteins, they trigger the release of inflammatory chemicals. One of the most notable chemicals released is histamine.

Histamine is responsible for many common symptoms, such as itching. Reactions are categorized into three groups based on these mechanisms: IgE-mediated, non-IgE mediated, or a hybrid of both types.

Symptoms can manifest in many different ways depending on the individual. Common signs include hives, skin rashes, and itching of the mouth, lips, or throat. Some people experience swelling, known as angioedema, in their face, eyelids, or tongue. Other symptoms involve the digestive system, such as vomiting, diarrhea, or abdominal pain. Respiratory issues like wheezing, shortness of breath, or a hoarse voice are also possible. If the reaction affects the respiratory tract and blood circulation, it is called anaphylaxis. If a person's blood pressure drops significantly during this time, they may enter anaphylactic shock.

Certain foods are much more likely to trigger these reactions than others. In the United States, nine specific allergens must be clearly listed on food labels. These include milk, eggs, peanuts, tree nuts, fish, shellfish, soy, wheat, and sesame. The inclusion of sesame was made mandatory following the FASTER Act signed by President Biden in April 2021. Peanuts are a member of the legume family and affect about 2% of the Western population. Peanut allergies often cause more severe reactions and anaphylaxis than other food allergies.

Tree nuts, such as almonds, cashews, and walnuts, are also common triggers.

Different types of food allergies behave differently as a person grows. Some allergies, such as those to milk, eggs, and soy, often resolve as children get older. For example, egg allergies affect about one in 50 children but are frequently outgrown by age five. However, allergies to nuts and shellfish typically do not go away. Shellfish is the most common food allergy found in adults and includes both crustaceans, like shrimp and lobster, and mollusks, like mussels and squid. Fish allergies are often more common in countries where fish consumption is high.

Exposure to allergens can happen through several different routes. While eating the food is the most common path, inhalation and skin contact can also cause sensitization. In certain jobs, such as seafood processing or industrial baking, workers may inhale airborne particles. This can lead to respiratory symptoms like "baker's asthma." Skin contact is also a factor, particularly for those with impaired skin barriers. For instance, peanut allergies are more common in adults who had oozing or crusted skin rashes as infants.

Managing food allergies requires careful planning and strict avoidance. It is vital to prevent cross-contact, which occurs when allergens are unintentionally transferred to safe foods. This often happens through shared cooking equipment or surfaces that were not properly cleaned. In the United States, the FDA distinguishes cross-contact from cross-contamination, which refers to biological or chemical contaminants. To prepare for emergencies, many people carry an epinephrine autoinjector. This device provides a dose of adrenaline to help manage severe reactions.

Wearing medical alert jewelry is another common safety measure.