An allergy is an immune system response to a foreign substance, or allergen, that’s not typically harmful to the body. Symptoms and treatments may vary depending on the type of allergy you have.

The immune system is responsible for keeping you healthy by fighting harmful pathogens.

It does this by creating antibodies called immunoglobulin. There are several types of immunoglobulins, which fight against possible agents like bacteria, viruses, parasites, and chemicals. Immunoglobin E (IgE) is a type that responds to certain substances and causes an allergic reaction.

Allergic reactions may involve a variety of symptoms, ranging from mild inflammation to life threatening situations.

According to the Centers for Disease Control and Prevention (CDC), 1 in 3 people have an allergy in the United States.

Keep reading to learn more about the types, symptoms, and causes of allergies, as well as how to treat them.

When to get immediate medical attention

Sometimes, allergic reactions may cause symptoms that could be life threatening, known as anaphylaxis.

If you or someone you know suddenly experiences any of the following symptoms, call 911 or get immediate medical attention:

  • swelling in the face, throat, and tongue
  • dizziness, confusion, fainting
  • difficulty breathing, swallowing, and speaking
  • wheezing or coughing
  • skin discoloration, such as blue, pale, or gray tongue

If you or the person has an epinephrine autoinjector, use it immediately. The shot counters allergic reactions until medical help arrives and could be lifesaving.

Learn more about what to do if someone has an allergic reaction.

There are several types of allergies, according to Allergy UK. These include:

Symptoms of allergies may depend on several factors, such as the type and severity of your allergy.

According to the American College of Allergy, Asthma, and Immunology (ACAAI), common allergy symptoms may include:

  • congestion
  • runny nose
  • sneezing
  • coughing
  • fatigue
  • headaches
  • rashes, such as hives
  • nausea
  • vomiting
  • fever
  • wheezing
  • difficulty breathing

Learn more about the most common allergy symptoms.

Skin allergy symptoms

Certain skin symptoms may indicate an allergic reaction.

For instance, you may experience tingling in your mouth after eating a food you’re allergic to. Or, you may experience an allergic reaction if your skin comes into direct contact with an allergen, known as contact dermatitis.

Symptoms of skin allergies may include:

  • rashes
  • hives
  • swollen, watery, or puffy eyes
  • itching
  • burning

Learn more about .

It’s still unclear why the immune system causes an allergic reaction when a normally harmless foreign substance enters the body.

However, researchers have identified several factors that may contribute to allergies, including:

  • older age
  • genetics
  • hormonal changes, especially in people assigned female at birth
  • immunological factors, such as weakened immune system
  • gut microbiome changes
  • having other allergies, such as atopic dermatitis

Several common allergens have also been identified, including foods, medications, and environmental irritants. The cause of allergies may depend on how you come into contact with it:

  • Ingestion: Foods like nuts, cow’s milk, sesame, fish, tree nuts, and shellfish may cause allergies. Some oral medications like penicillin may also trigger a reaction.
  • Inhaling: Several environmental irritants, such as pollution, pet dander, mold, pollen, and dust mites, can trigger allergies.
  • Direct contact: Some allergies are caused by direct contact with allergens, such as insect stings, the sun, certain plants, latex, and certain metals.

A doctor will first ask about your symptoms and perform a physical exam.

They may ask about anything unusual you may have eaten recently and any substances you may have come in contact with. For example, if you have a rash on your hands, they may ask if you put on latex gloves recently.

To confirm an allergy, they may order several tests, including:

  • Blood test: This can help detect the presence of IgE, which are cells that react to allergens.
  • Skin prick test: Small amounts of an allergen are pricked, brushed, or scratched against your skin to see if there’s an allergic reaction.

Learn more about allergy testing and diagnosis.

Avoiding the allergen that triggers the reaction is the best way to prevent allergies. If that’s not possible, there are treatment options available.

Medication

Allergy treatment usually includes over-the-counter or prescription medications, which are available as nasal sprays, pills, liquids, and topical ointments.

Some allergy medications may include:

It’s important to work with a healthcare professional to develop the best management plan for your allergies.

Immunotherapy

Immunotherapy is a treatment that involves administering small doses of an allergen to help your body become used to it over time.

There are two types of immunotherapy:

  • Injections: This involves several injections over a few years. It’s most helpful for allergens like pollen, pet dander, insect stings, and asthma.
  • Sublingual immunotherapy (SLIT): This involves placing small doses of allergens under your tongue. It’s best for asthma and nasal allergies, such as dust mites, ragweed, and grass.

Successful immunotherapy can prevent allergy symptoms from returning.

Emergency epinephrine

If you have a severe, life threatening allergy, you’ll most likely have to carry an emergency epinephrine autoinjector. This is the first-line treatment for anaphylaxis.

This shot counters allergic reactions until medical help arrives. Common brands of this treatment include:

  • Epipen
  • Twinject
  • Emerade
  • Jext

Natural remedies

Several natural remedies and supplements could help relieve allergy symptoms. These may include:

It’s important to note that limited research supports the efficacy of these natural remedies. They should be used alongside medical treatments, such as medication and immunotherapy.

Some home remedies may also trigger allergy symptoms in some people. For instance, some dried teas use flowers and plants closely related to plants that might be causing you to sneeze.

Learn more about 15 natural remedies for allergies.

There’s no way to prevent allergies from developing, but there are ways to prevent symptoms.

The best way to prevent allergy symptoms is to avoid the allergens that trigger them.

Other tips to prevent allergies include:

  • following your allergy treatment plan, such as taking medications
  • trying an elimination diet
  • reading food labels
  • asking questions about ingredients when dining out
  • installing proper air filters in your home
  • regularly dusting your home

Learn more about how to prevent allergic reactions.

The most severe complication of allergies is anaphylaxis.

If not treated immediately, anaphylaxis may lead to death in less than 5 minutes.

Allergies and allergy treatments may lead to complications that affect your heart, circulation, and breathing. For instance, people with heart disease are at a greater risk of heart attack.

If you have allergies, speak with a healthcare professional about potential complications. They could help develop the best management plan for you.

Allergies may be associated with other conditions or cause similar symptoms.

Asthma and allergies

Asthma is a common respiratory condition that can make breathing more difficult and narrow the air passageways in the lungs.

Allergies are the most common asthma trigger, according to the Allergy and Asthma Foundation of America.

Allergic asthma is when these conditions occur together.

Allergies vs. cold

Allergies and the common cold may have similar symptoms, such as runny nose, headache, and coughing.

However, some additional signs and symptoms may help you distinguish between them. For instance, allergies may cause skin rashes and itchy eyes, while the common cold can lead to body aches and even fever.

The common cold may last up to 2 weeks, while allergies like hay fever could last a few months.

Learn more about the differences between allergies and the common cold.

Hay fever cough vs. chronic cough

Hay fever may produce symptoms that include sneezing, itchy eyes, and coughing.

Chronic cough is a cough that lasts more than 8 weeks.

Hay fever cough is usually temporary because it’s typically a seasonal allergy. However, sometimes hay fever may cause a dry cough that lasts longer than 3 weeks.

Allergies and bronchitis

Bronchitis is inflammation of the lungs, typically caused by a viral infection, such as influenza or the common cold.

Acute bronchitis may last up to 3 weeks, but chronic bronchitis can linger for months and return frequently.

Bronchitis may result from common allergens, such as pollen, cigarette smoke, and perfume, among others.

Your child may have an allergy if they experience frequent symptoms like coughing, sneezing, skin rashes, and nausea, according to the ACAAI.

According to the CDC, 1 in 4 children in the United States experienced an allergy in 2021.

The three most common allergies in children are:

  • hay fever
  • skin allergies
  • food allergies, with peanuts and cow’s milk being the two most common

What are the most common allergy symptoms?

Common allergy symptoms include itchy eyes, sneezing, facial tenderness, headache, fatigue, difficulty breathing, wheezing, dizziness, lightheadedness, and nausea, among others.

What are the 9 major food allergies?

The 9 most common food allergies include cow’s milk, sesame, eggs, fish, wheat, shellfish, soy, peanuts, and tree nuts.

How to help with allergies?

Treatment for allergies may include medications like antihistamines, decongestants, and epinephrine autoinjectors, as well as immunotherapy and home remedies.

Allergies are common and don’t have life threatening consequences for most people.

However, if you’re at risk of anaphylaxis, it’s important to carry an epinephrine autoinjector and use it immediately if you experience allergy symptoms. This could be lifesaving.

Most allergies are manageable with avoidance, medications, and lifestyle changes. Working with a doctor can help reduce major complications and make life more enjoyable.