Allergy

Sometimes your body gets confused.

It thinks tiny things are bad. These things might be dust or pollen.

Your body tries to fight these things. This can make you sneeze or cough. It might also make your eyes red and itchy.

Many things can cause this. Some people react to certain foods. Others react to insect stings.

Some people have itchy skin or rashes. This can happen from things like latex.

Doctors can help you find what causes it. You can also use medicine to feel better.

An allergy happens when your body makes a mistake. Your immune system is meant to protect you. It fights off germs that can make you sick. But sometimes, it thinks harmless things are threats. We call these things allergens.

Common allergens include pollen, certain foods, and insect stings. Dust mites can also cause reactions.

Some people react to latex, which is a material used in masks.

When an allergen enters your body, it triggers a set of steps. Tiny parts of your blood called IgE antibodies find the allergen. These antibodies attach to cells called mast cells. This causes the cells to let out chemicals like histamine.

These chemicals cause symptoms. You might sneeze, cough, or have itchy eyes. Some people get skin rashes or hives. In very bad cases, a person may have anaphylaxis. This is a severe reaction that affects many parts of the body. It can cause swelling or trouble breathing. Doctors can use medicine or adrenaline to help.

An allergy is a mistake made by your immune system. Usually, your body protects you from germs that cause sickness. In an allergy, your body thinks a harmless thing is a threat. We call these harmless things allergens.

This mistake can lead to many different allergic diseases. Some people get hay fever or itchy eyes. Others might face asthma or skin problems like eczema. These reactions can affect many parts of the body at once.

There is a specific way this reaction works inside you. First, tiny parts in your blood called IgE antibodies find the allergen. These antibodies attach to special cells called mast cells or basophils.

This connection tells the cells to release chemicals. One important chemical is called histamine. These chemicals cause the symptoms you feel. They might make your nose run or your skin swell.

People have studied these reactions for a long time. The word "allergy" was first used by Clemens von Pirquet in 1906. Scientists now know that many things can cause these reactions. Allergens can be things you breathe, eat, or touch.

Common triggers include pollen, dust mites, and certain foods. Some people also react to insect stings or materials like latex.

Allergies are very common in the world today. About 20% of people in the developed world have allergic rhinitis. Food allergies affect 10% of adults and 8% of children. In the United States, crustacea is a common food allergy. Many children can even outgrow peanut allergies over time. Egg allergies also affect about one to two percent of children.

Doctors have many ways to help people with allergies. They can use skin or blood tests to find the cause.

One way to treat allergies is to avoid the allergen entirely. People can also use medicines like antihistamines or steroids. For very severe reactions called anaphylaxis, doctors use injectable adrenaline. Some people try immunotherapy to help their bodies adjust. This method slowly exposes a person to small amounts of an allergen.

An allergy is an exaggerated immune response by the body. It occurs when the immune system mistakenly identifies a harmless substance as a dangerous threat. These substances are known as allergens.

This biological mistake can lead to various allergic diseases. These include hay fever, allergic conjunctivitis, and allergic asthma. Other conditions include atopic dermatitis, food allergies, and anaphylaxis. Symptoms vary depending on the part of the body affected. They can include red eyes, itchy rashes, sneezing, or coughing. Some people experience shortness of breath or swelling.

The biological mechanism of an allergy is a specific chain of events. It begins when immunoglobulin E antibodies, or IgE, bind to an allergen. These IgE antibodies then attach to receptors on specific cells called mast cells or basophils.

Once this binding occurs, it triggers the cells to release inflammatory chemicals. One of the most important chemicals released is histamine. This chemical release causes the physical symptoms of an allergy. For example, when an allergen enters the skin, mast cells activate. This increases the permeability of blood vessels, leading to fluid leakage and swelling.

Allergic reactions can affect many different organ systems. If allergens are airborne, such as pollen or dust, they often affect the nose, eyes, and lungs. Allergic rhinitis, or hay fever, irritates the nose and causes sneezing. Inhaled allergens can also cause the lungs to produce more mucus. This can lead to wheezing or shortness of breath.

Food allergies often affect the gastrointestinal tract. This can cause abdominal pain, bloating, vomiting, or diarrhea. Some allergies, like insect stings or certain medications, can cause a systemic response. This is called anaphylaxis. Anaphylaxis can affect the digestive, respiratory, and circulatory systems simultaneously. It can cause low blood pressure, swelling, or even coma.

There are many different types of allergens that people encounter. Common airborne allergens include pollen and house dust mites.

Dust mite allergies are often triggered by the droppings of these mites. Certain foods are also major triggers for allergic reactions. About 90% of food allergies are caused by cow's milk, soy, eggs, wheat, peanuts, tree nuts, fish, and shellfish. Insect stings are another frequent source of allergies. Additionally, some people react to materials like latex.

Even common medications, such as penicillin or aspirin, can cause reactions.

Scientists have been studying these responses for over a century. The term "allergy" was first used by Clemens von Pirquet in 1906. Since then, researchers have identified various risk factors. These include host factors like heredity, sex, race, and age. Heredity is considered the most significant factor. However, there is a recent increase in allergic disorders that cannot be explained by genetics alone. Environmental factors also play a role. These include changes in dietary habits, environmental pollution, and levels of allergens. Changes in exposure to infectious diseases during early childhood are also considered candidates.

Allergies are very common in the modern world. In developed nations, about 20% of people suffer from allergic rhinitis. Atopic dermatitis affects about 20% of people at some point in their lives. Food allergies affect 10% of adults and 8% of children.

The rates of asthma vary by country, ranging from 1% to 18%. Anaphylaxis is less common, occurring in between 0.05% and 2% of the population. These numbers show how widespread these conditions are globally. Understanding these statistics helps researchers track how allergy rates appear to be increasing.

Doctors use several methods to diagnose and treat allergies. A person's medical history is often the first step in diagnosis. Doctors may also use skin or blood tests to confirm a specific allergy.

One primary treatment is avoiding known allergens. Medications like antihistamines and steroids are also used to manage symptoms. For severe cases of anaphylaxis, injectable adrenaline, also called epinephrine, is recommended. Some people use allergen immunotherapy. This involves gradually exposing the person to larger amounts of an allergen. This can be useful for hay fever or insect bite reactions.