Allergies: Symptoms, Reaction, Treatment & Management (2023)


Allergies: Symptoms, Reaction, Treatment & Management (1)

What are allergies?

Allergies are your body’s reaction to a foreign protein. Usually, these proteins (allergens) are harmless. However, if you have an allergy to a particular protein, your body’s defense system (immune system) overreacts to its presence in your body.

What is an allergic reaction?

An allergic reaction is the way your body responds to an allergen.

If you have allergies, the first time you encounter a specific allergen, your body responds by creating immunoglobulin E (IgE). Your immune system makes antibodies to form IgE.

IgE antibodies bind to mast cells (allergy cells) that live in your skin, respiratory tract (airways) and the mucus membrane in the hollow organs that connect to each other from your mouth to your anus (gastrointestinal or GI tract).

The antibodies find the allergens in your body and help remove them by taking them to the mast cell (allergy cell), where they attach to a special receptor. This causes the allergy cell to release histamine. Histamine is what causes your allergy symptoms.

How common are allergies?

Allergies are very common.

More than 50 million people in the United States have an allergic reaction each year. They’re the sixth-leading cause of long-term illness in the United States.

Who do allergies affect?

Allergies can affect anyone.

You’re more likely to have or develop allergies if your biological parents have allergies.

Symptoms and Causes

What are the most common allergies?

The most common allergies include:

Certain foods

Food allergies develop when your body releases a specific antibody to a particular food. An allergic reaction occurs within minutes of eating the food, and symptoms can be severe. Symptoms may include:

(Video) Allergies: Symptoms, Reaction, Treatment & Management - Video for Kids

  • Itching all over your body (generalized pruritus).
  • Itching in just one certain part of your body (localized pruritus).
  • Nausea and vomiting.
  • Hives.
  • Swelling around your mouth, including your throat, tongue or face.

If you have an IgE-mediated food allergy, symptoms may also include anaphylaxis. It may present as any one of the above symptoms or a combination of the above symptoms. It usually occurs within 30 minutes of ingesting a food you’re allergic to.

In adults, the most common food allergies are:

  • Milk.
  • Eggs.
  • Wheat.
  • Soy.
  • Peanuts.
  • Tree nuts.
  • Shellfish.

In children, the most common food allergies are:

  • Milk.
  • Eggs.
  • Wheat.
  • Soy.
  • Peanuts
  • Tree nuts.


Inhalant allergies are airborne substances that you inhale (breathe in). They include allergens that may affect you throughout the year (perennial allergens) and seasonal allergens.

Inhalant allergy symptoms include:

  • Runny nose.
  • Stuffy nose.
  • Itchy nose.
  • Sneezing.
  • Itchy eyes.
  • Watery eyes.

If you have asthma, inhalant allergies can also trigger or worsen your symptoms, including wheezing and shortness of breath.

Perennial allergens include:

  • Pets. Pet allergens include certain proteins in animal fur, skin (dander), urine (pee) and saliva (spit).
  • Dust mites. Dust mites are tiny, eight-legged relatives of spiders. They’re too small to see with your eyes. They live in dust and the fibers of household objects, such as pillows, mattresses, carpets and upholstery.
  • Cockroaches. Cockroaches are reddish-brown insects that are 1.5 to 2 inches (in) long. The proteins in their feces (poop), spit, eggs and dead body parts can cause allergic reactions.
  • Molds. Molds are tiny fungi (plural of fungus). They have spores that float in the air, like pollen. Common mold allergies include Aspergillus, Cladosporium and Alternaria.

Seasonal allergies include pollens. Pollen is microspores from trees, grass or weeds that appear as a fine dust on surfaces or float in the air. Tree pollens generally appear in the spring, while weed pollens generally appear in the fall.


Certain medications can cause an allergic reaction. The medicines may be herbal, over-the-counter (OTC) or prescription.

Common medications that cause allergies include:

  • Antibiotics.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs).
  • Insulin.
  • Chemotherapy drugs.

Symptoms include:

  • Rash.
  • Hives.
  • Itching.
  • Shortness of breath.
  • Swelling.


Latex allergies develop after repeated contact with natural rubber latex.

Common natural rubber latex products include:

(Video) Allergy - Mechanism, Symptoms, Risk factors, Diagnosis, Treatment and Prevention, Animation

  • Rubber gloves.
  • Balloons.
  • Condoms.
  • Bandages.
  • Rubber balls.

The most common reaction to latex is skin irritation (contact dermatitis). It manifests as a rash on the area of skin that touched the latex. It may develop within minutes of exposure to latex. Other symptoms may include:

  • Hives.
  • Runny nose.
  • Itchy nose.
  • Difficulty breathing.

Venoms/stinging insects

Stinging insects can inject venom, which is a toxic substance. The venom in insect stings can cause an allergic reaction. The most common stinging insects that cause allergic reactions include:

  • Bees.
  • Fire ants.
  • Hornets.
  • Wasps.
  • Yellow jackets.

Venom symptoms are consistent with anaphylaxis. They may include:

  • Difficulty breathing.
  • Hives.
  • Swelling in your face, mouth or throat.
  • Wheezing.
  • Difficulty swallowing.
  • Rapid pulse.
  • Dizziness.
  • Drop in blood pressure.

Can allergies cause a fever?

No, allergies can’t cause a fever.

What causes allergies?

Allergies develop when your immune system reacts to a foreign substance or protein.

Are allergies contagious?

No, allergies aren’t contagious. You can’t spread your allergies to another person.

Diagnosis and Tests

How are allergies diagnosed?

If you think you have allergies, don’t wait to see if your symptoms go away. If your symptoms last longer than a week or two or tend to come back during certain times of the year, make an appointment with an allergist.

An allergist is a healthcare provider who specializes in allergies. They can help diagnose your allergies through tests.

How do I test for allergies?

There are different types of allergy tests. The most common allergy tests are skin prick tests and blood tests.

Skin prick (scratch) tests can identify the allergens that cause your allergy symptoms. An allergist will use a thin needle to prick your skin with a tiny amount of different possible allergens. They then check to see if your skin reacts to the allergen.

Blood (IgE) tests can also identify allergies. However, they’re not as sensitive as skin prick tests. Blood tests evaluate IgE antibodies that your immune system produces against a specific protein.

Management and Treatment

How are allergies treated?

Avoiding allergens is an important treatment approach. However, it often doesn’t completely end allergic reactions. Over-the-counter and prescription allergy medications are also a solution to managing your allergies. These may include:


  • Fexofenadine.
  • Loratadine.
  • Cetirizine (All Day Allergy-D® or Zyrtec®).

Nasal sprays

These medications are very effective and safe to use daily but they may take a few days to a week to kick in.

  • Fluticasone nasal spray (Flonase® or ClariSpray®).
  • Cromolyn sodium.
  • Antihistamine nasal sprays


These medications should be used cautiously when treating allergies due to higher side effects and concerns related to long-term use.

  • Oxymetazoline.
  • Phenylephrine (Sudafed PE® or Sudogest PE®).
  • Pseudoephedrine (Contac® or Sudafed®).

Asthma medications

  • Inhaled or oral bronchodilators.
  • Inhaled steroids.
  • Oral antileukotrienes, including montelukast, zafirlukast and zileuton.
  • Injected drugs, including omalizumab, dupilumab or benralizumab.


A healthcare provider may recommend immunotherapy (allergy shots) and/or sublingual immunotherapy (allergy drops) if you can’t manage your allergy symptoms through over-the-counter and prescription medications and avoiding allergens. The provider will expose you to small amounts of allergens and gradually increase the dosage over several months. Gradual exposure creates a tolerance to the allergen.

Nasal saline irrigation

A neti pot is an over-the-counter device that pushes a saline (salt) solution through your nasal passages. It helps clear out mucus and allergens trapped inside your nasal passages.

What is the best treatment for allergies?

Nasal steroid sprays are generally the most effective medication for people with allergic rhinitis symptoms. Antihistamines block some of the effects of histamine and may offer additional benefits. Immunotherapy helps create a tolerance to allergens and can improve many of the symptoms related to inhalant allergy exposure.

Remember, your body is unique. What over-the-counter or prescription medications work for one person may not work well for you.

Talk to a healthcare provider. They can help recommend the best treatment for you.

What can/can’t I eat/drink if I have food allergies?

If you have food allergies, avoid any products that contain the allergens. By law, manufacturers must include all ingredients on the label of packaged foods for sale in the United States.

You should also consider other possible food allergy exposures. Some nonfood items may contain food allergens, and labeling laws don’t apply to nonfood items.

During the manufacturing process, some food items share equipment or surfaces. Look for labels that state whether the product shared equipment with possible food allergens.

(Video) Anaphylaxis, Animation


How can I prevent allergies?

The best way to prevent allergies is to avoid allergens. You can also take antihistamines or other medications daily to help control your symptoms and reduce your allergic reaction.

(Video) Allergy - How To Deal With A Severe Allergic Reaction

If you have animal allergies, avoid petting, hugging or kissing animals. Don’t allow them in your bedroom or on your furniture.

Regularly vacuuming rugs, carpets and other surfaces helps remove dust, animal dander, pollen and other allergens.

High-efficiency particulate (HEPA) air filters can also help. These air purifiers remove airborne allergens from your environment.

Outlook / Prognosis

What can I expect if I have allergies?

Living with allergies can be challenging. Symptoms can range from mild to severe. However, with caution, you can lead a fulfilling life. Your healthcare provider can recommend resources, support groups and specialists to help you.

How long can allergies last?

Your allergies will last as long as your allergen exposure. Once you’re no longer around allergens, your symptoms should go away after a few hours. However, if you have inhalant allergies, your symptoms may last for several days or longer due to ongoing exposure to pets, dust mites and pollens.

Can children outgrow allergies?

Yes, some children can outgrow their allergies. However, it depends on the type of allergy and the severity of your child’s allergy.

Living With

When should I see my healthcare provider?

Go to the ER or call 911 immediately if you start showing symptoms of anaphylaxis.

What questions should I ask my healthcare provider?

  • How can you tell that I have allergies?
  • What am I allergic to?
  • Do I have mild, moderate or severe allergies?
  • What medications do you recommend?
  • Should I take allergy medications every day or only when I develop symptoms?
  • What’s the complete list of side effects of your recommended allergy medication?
  • Can you recommend an allergist?
  • Can you recommend a dietitian?

Frequently Asked Questions

What is the difference between a cold and allergies?

A cold is a contagious upper respiratory infection. Viruses cause colds.

Allergies are your immune system’s response to an allergen. Viruses aren’t allergens.

A cold shares many of the same symptoms as allergies. These include sneezing, runny nose, cough and congestion. However, there are differences between cold symptoms and allergy symptoms.

(Video) Allergies - Causes, Symptoms and Treatment Options

  • Mucus. If you have allergies, your mucus is usually clear and watery. If you have a cold, your mucus is generally thicker and discolored (yellow or green).
  • Eyes. If you have allergies, your eyes may be itchy, watery or red. These symptoms don’t usually develop if you have a cold.
  • Duration. Without treatment, allergy symptoms may last for weeks or months until you’re no longer around the allergen. Cold symptoms usually go away after about 10 days.

A note from Cleveland Clinic

Allergies occur when your immune system mistakenly triggers an allergic reaction to an allergen. Allergic reaction symptoms include congestion, watery eyes, a runny nose, vomiting and, in severe cases, anaphylaxis.

Allergies can be incredibly frustrating if you don’t know what’s triggering your immune system. However, a healthcare provider can help provide relief. They can conduct tests to pinpoint your allergies and prescribe medications. They can also refer you to specialists or support groups.


What are 3 ways to treat an allergic reaction? ›

Apply hydrocortisone cream or calamine lotion. Cover the area with a bandage. If there's swelling, apply a cold compress to the area. Take an antihistamine to reduce itching, swelling, and hives.

How do you flush out an allergic reaction? ›

Keep yourself hydrated. "While your body is purging the allergen food from it is system, the best thing you can do is drink plenty of fluids," Zeitlin says. Water is always a good idea, but you can also sip on low calorie sports drinks to replenish the electrolytes you're likely losing, Zeitlin says.

What are the 3 stages of an allergic reaction? ›

These antibodies travel to cells that release histamine and other chemical mediators, which cause allergy symptoms to occur. The human body carries out an allergic cascade in three stages: sensitization, “early-phase,” and “late-phase.”

Which medication is used to treat the body's reaction to allergies? ›

Antihistamines. Antihistamines block histamine, a symptom-causing chemical released by your immune system during an allergic reaction.

Is Benadryl good for allergic reaction? ›

An antihistamine pill, such as diphenhydramine (Benadryl), isn't enough to treat anaphylaxis. These medications can help relieve allergy symptoms, but they work too slowly in a severe reaction.

What is the best home remedy for allergic reaction? ›

A nonprescription oral antihistamine, such as loratadine (Claritin), cetirizine (Zyrtec Allergy) or diphenhydramine (Benadryl Allergy, others), may help relieve itching. Apply cool, wet compresses. Covering the affected area with cool, moist bandages or dressings can help soothe the skin and prevent scratching.

How long does it take for an allergic reaction to stop? ›

It can take anywhere from a few hours to 10 days. Typically, it takes from 12 hours to 3 days. Even with treatment, symptoms can last 2 to 4 weeks. Learn more about contact dermatitis causes, symptoms, and treatments.

How long does it take for an allergic reaction to fully go away? ›

A skin reaction from allergic contact dermatitis will go away, but usually takes from 14 to 28 days. If you come in contact with something that can cause allergic contact dermatitis (like poison ivy), scrub the skin with soap and water right after.

At what point do I go to the doctor for an allergic reaction? ›

"If you have a simple rash, and you're itching, you can probably go to urgent care. But if you have a rash and vomiting, you should go to the ER." An anaphylactic allergic reaction can be life-threatening and requires immediate medical treatment.

What is the most severe symptom of an allergic reaction? ›

Anaphylaxis. This sudden, severe allergic reaction can cause death if it isn't treated right away at the emergency room. You may not know you're allergic to something until anaphylaxis happens. Signs include trouble breathing, pale or blue skin, hives, itching, vomiting, or anxiety.

What is the immediate treatment for allergic reactions? ›

H1 antihistamines — Epinephrine is first-line treatment for anaphylaxis, and there is no known equivalent substitute. H1 antihistamines (such as diphenhydramine or cetirizine) relieve itch and hives.

What are the 4 types of allergic reactions? ›

Type I: reaction mediated by IgE antibodies. Type II: cytotoxic reaction mediated by IgG or IgM antibodies. Type III: reaction mediated by immune complexes. Type IV: delayed reaction mediated by cellular response.

When should you not give Benadryl? ›

While it is true that Benadryl is a common treatment used in adults and older children, diphenhydramine but can be dangerous for children under two years old. And after two it should be used carefully with a doctor's advice on frequency and dosage. Therefore, Benadryl is not safe for infants as a general rule.

What is better than Benadryl for allergies? ›

Claritin is usually recommended over Benadryl for allergic rhinitis and other allergy symptoms. Both drugs have similar effectiveness but Claritin has less sedating side effects. Claritin only needs to be taken once daily which may be preferred for some people.

What stops a severe allergic reaction? ›

Epinephrine (adrenaline) to reduce the body's allergic response. Oxygen, to help you breathe. Intravenous (IV) antihistamines and cortisone to reduce inflammation of the air passages and improve breathing. A beta-agonist (such as albuterol) to relieve breathing symptoms.

Do allergic reactions go away without medication? ›

Skin allergy symptoms like redness, itching, and swelling often go away on their own in a week or two, with or without treatment. You can do some things to make it more comfortable in the meantime.

What is a natural antihistamine? ›

Summary. Natural antihistamines may help you control your seasonal allergies. Common ones are stinging nettle, vitamin C, quercetin, butterbur, bromelain, and probiotics. Some alternative practices—such as acupuncture, nasal irrigation, and exercise—may also help you manage symptoms.

Can allergic reactions subside on their own? ›

Anaphylactic reactions can vary greatly from person to person, or from one reaction to the next. The symptoms may get worse within only a few minutes. They then often stay at the same level of severity for a while and then go away again on their own.

Why am I having allergic reactions all of a sudden? ›

Maybe you ate a certain food or touched/inhaled something, like dust or certain plants. These things are called allergy triggers. The most common type of skin allergy is contact dermatitis, also called atopic dermatitis. It happens when you're exposed to an irritant, such as laundry detergent, latex, or poison ivy.

What happens if an allergic reaction goes untreated? ›

Untreated allergies can get worse, with more severe allergy attacks occurring over time. These frequent or prolonged allergic reactions can also weaken your immune system and set you up for dangerous complications, such as bacterial or fungal infections in the sinuses, lungs, ears or skin.

How much Benadryl can I take for an allergic reaction? ›

For mild allergy symptoms in adults and children ages 12 years and older, 25 mg to 50 mg of Benadryl is recommended every 4 to 6 hours. The most you should take in a 24-hour period is 300 mg. For children ages 6 to 11 years, the recommended dose is 12.5 mg to 25 mg every 4 to 6 hours as needed.

What is considered a serious allergic reaction? ›

Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as peanuts or bee stings.

Should you always go to hospital for allergic reaction? ›

Immediate action required: Call 999 if:

you get a skin rash that may include itchy, red, swollen, blistered or peeling skin. you're wheezing. you get tightness in the chest or throat. you have trouble breathing or talking.

What to drink when your allergies are acting up? ›

If you feel stuffy or have postnasal drip from your allergies, sip more water, juice, or other nonalcoholic drinks. The extra liquid can thin the mucus in your nasal passages and give you some relief. Warm fluids like teas, broth, or soup have an added benefit: steam.

Does drinking water help with allergies? ›

Be sure you're drinking enough fluids to stay hydrated during allergy season. "Studies have shown that when you're dehydrated your body produces higher histamine levels and that drives allergies," Ogden said.

What happens to your body when you have an allergic reaction? ›

When a harmless substance such as dust, mold, or pollen is encountered by a person who is allergic to that substance, the immune system may over react by producing antibodies that "attack" the allergen. The can cause wheezing, itching, runny nose, watery or itchy eyes, and other symptoms.

What is the first line of treatment for allergic reaction? ›

H1 antihistamines — Epinephrine is first-line treatment for anaphylaxis, and there is no known equivalent substitute. H1 antihistamines (such as diphenhydramine or cetirizine) relieve itch and hives.

What is the best treatment of allergic? ›

What is the best treatment for allergies? Nasal steroid sprays are generally the most effective medication for people with allergic rhinitis symptoms. Antihistamines block some of the effects of histamine and may offer additional benefits.

How long does it take for an allergic reaction to clear up? ›

A skin reaction from allergic contact dermatitis will go away, but usually takes from 14 to 28 days. If you come in contact with something that can cause allergic contact dermatitis (like poison ivy), scrub the skin with soap and water right after.

When should you go to the ER for an allergic reaction? ›

“If you have a raised, itchy rash, you'll probably benefit from oral steroids, like prednisone,” Dr. Larson says. “But if you're experiencing wheezing, throat swelling or difficulty swallowing, or you're feeling lightheaded or faint, you need to seek emergency care.”


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