How Long Do Allergic Reactions Last? Causes, Symptoms, and Relief

How long do allergy symptoms last?

Allergy symptoms and reactions will typically last as long as you are exposed to the allergens that cause your allergic reaction. If you are exposed to an allergen for weeks or months, you can experience symptoms throughout that entire period unless you limit exposure or get an effective treatment plan.

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If you've ever had an allergic reaction, you know they can range from annoying to potentially life-threatening. Allergic reactions can be scary, especially if you don't know how long they will last. The good news is that most allergic reactions are not life-threatening and will resolve on their own.

But exactly how long does an allergic reaction last? This article delves deeper into allergic reactions, including their symptoms, causes, and how long they last. Read on for everything you need to know about allergic reactions.

What Is an Allergic Reaction?

An allergic reaction occurs when your body comes into contact with an allergen that triggers an immune response. You can have an allergic reaction when allergens come into contact with your respiratory tract, eyes, skin, nose, or gastrointestinal tract.

When this happens, your body releases antibodies designed to protect you from threats to your immune system. These antibodies cause cells in your body to release histamine, which causes the symptoms associated with allergies to try to remove the allergens from your body. Histamine dilates your blood vessels, which can cause swelling and irritation. Histamine can also increase mucus production, leading to a runny nose or congestion.

An allergic reaction can affect a specific body part or your entire body. While reactions are mild for most people, they can be life-threatening for others. One of the most severe allergic reactions is anaphylaxis. It occurs when the throat or airway begins to swell, making it difficult to breathe.

What Are the Types of Allergic Reactions?

Scientists classify allergic reactions into four types: types I, II, III, and IV. The kind of reaction you have will determine the type of symptoms you experience and how long the reaction lasts. Here is an overview of each type of reaction.

Type I Reactions

These are immediate hypersensitivity reactions, also known as anaphylactic reactions. They are the most severe and can occur within minutes of contact with an allergen. Symptoms of a type I reaction include hives, difficulty breathing, swelling of the throat or tongue, chest pain, and dizziness.

If you experience a severe allergic reaction, immediately seek emergency medical attention.

Type II Reactions

These are cytotoxic reactions, which occur when antibodies attach to allergens on cells and damage or destroy them. This reaction is most commonly seen in people with a blood disorder called hemolytic anemia. The body produces antibodies that destroy red blood cells.

Type III Reactions

These are immune complex-mediated reactions, which occur when antibodies and allergens form complexes that deposit in tissues and cause inflammation. You will notice this allergic reaction in people with autoimmune diseases like lupus or rheumatoid arthritis.

Type IV Reactions

These are delayed hypersensitivity reactions, which occur when the immune system overreacts to an allergen and causes inflammation. This type of reaction is most commonly seen in people with contact dermatitis. This condition causes a rash when the skin comes into contact with an allergen.

What Are the Symptoms?

Allergic reactions can cause a wide range of symptoms, from mild to severe. The symptoms you experience will largely depend on the type of reaction you have. Here is a closer look at some of the most common mild symptoms of allergies:

Mild Allergy Symptoms

Allergic rhinitis is a condition that is commonly referred to as hay fever. It occurs when your nose becomes swollen and itchy due to an allergen. Symptoms of hay fever include sneezing, a runny or stuffy nose, and itchy eyes. Symptoms can also include:


An allergic reaction can cause itchy skin, eyes, nose, mouth, or ears. If you experience itchiness from an allergy reaction, you will feel an uncontrollable itching sensation that makes you scratch the itchy area. Itching can also cause redness.

Watery Eyes

This symptom is caused by the histamine released in response to an allergen. Histamine causes the blood vessels in your eyes to swell and leak fluid.

Scratchy Throat

An itchy or scratchy throat is a common symptom of allergies, especially those caused by pollen or pet dander. The feeling can be similar to having a cold. However, it's usually not accompanied by other symptoms like a runny nose or fever.


A rash is a cluster of raised bumps or patches on your skin. Rashes can be itchy and painful, and their appearance will differ depending on your skin tone. For instance, if the rash is due to contact dermatitis, the rash will have visible borders and appear in the area where your skin touched the irritant.


Hives are also referred to as urticaria, and they are itchy raised welts that form on your skin due to an allergy. The hives can be flesh-colored, pink, or red and hurt or sting. You are likely to have hives if you have an allergic reaction caused by certain foods, medicines, or an irritant in your surroundings.


Allergic reactions can cause swelling in your throat, lips, tongue, and other body parts. This is usually due to the release of histamine, which dilates your blood vessels and causes fluid to leak into your tissues.

Severe Allergy Symptoms

Severe allergic reactions can lead to the following symptoms:

  • Diarrhea
  • Abdominal pain or cramping
  • Wheezing
  • Chest pain or tightness
  • Difficulty swallowing
  • Anxiety
  • Trouble breathing
  • Face swelling
  • Unconsciousness
  • Flushing of the face
  • Weakness

If you have anaphylaxis, your symptoms will be more life-threatening. They will include the following:

  • A sudden drop in blood pressure
  • Airway swelling
  • Inability to breathe

If you have such symptoms, you should seek immediate medical attention.

Common Allergy Triggers

You can develop an allergic reaction when your body's immune system overreacts to different allergens. Some of the most common triggers of allergies include:


Pollen is a fine powder that plants release. It contains proteins that can cause an allergic reaction in some people. The symptoms of pollen allergies are usually at their worst during spring and summer when plants are in full bloom. Pollen allergies are usually caused by pollen from trees, grasses, and weeds.

Animal Dander

Your pets might be the cause of your allergies. Pets have dander—tiny flakes of dead skin that they shed. If you are allergic to pet dander, coming into contact with their dander, saliva, or urine can cause allergy symptoms like hives, skin rashes, or contact dermatitis.


Mold is a type of fungus that can be found both indoors and outdoors. If you are allergic to mold, your immune system will overreact when you inhale the mold spores. You will experience symptoms like a runny nose, coughing, and watery eyes.

Dust Mites

Dust mites are tiny creatures that thrive in warm and humid environments and feed on the skin cells you and your family shed. They will likely find shelter in your bedding, upholstered furniture, and carpets. If you are allergic to dust mites, they can cause asthma and other respiratory problems.

Others Allergens

Many other potential allergens exist. These include insect stings, latex, certain foods, food additives, and some medications. Common foods that trigger allergies include peanuts, tree nuts, fish, shellfish, and eggs. You can be allergic to medications like penicillin.

How Long Does an Allergic Reaction Last?

An allergic reaction can last for varying amounts of time. An allergic reaction can typically last from a few hours to a few weeks. If you have prolonged exposure to your allergen, your allergic reaction will usually last longer.

The symptom length of an allergic reaction also depends on the allergen and the severity of your response. There is no one-size-fits-all answer, as the reactions will last for varying lengths. 

For instance, although hives appear immediately after exposure to an allergen, they can go away after only a few minutes or hours. Contact dermatitis will last two to four weeks, after which the rash will clear up. However, if you are exposed to allergens like pollen during pollen season, your allergic reaction may continue for several weeks or months as long as you continue to be exposed or until the season is over.

When to See an Allergy Doctor

If you think you are experiencing allergy symptoms, it is important to meet with an allergist and take an allergy test to confirm. Testing is an important step to take when experiencing potential allergy symptoms. Doing so will confirm if you have allergies and identify what you are allergic to. This will give you a better understanding of your sensitivities and help you develop a plan for managing them.

However, if you are experiencing severe allergy symptoms like difficulty breathing or swallowing, it is important to seek immediate medical care. You should be especially careful if you have a history of severe reactions like anaphylaxis.

Ways to Diagnose an Allergy Reaction

Allergy testing can be done through either a skin prick test or an at-home allergy test. The easiest way to complete your allergy test is to use Wyndly’s at-home test. This test is convenient and easy to take from the comfort of your home. Get your test today!

Skin Prick Test

This old-fashioned allergy testing method requires you to visit a doctor’s office to find out the allergen that triggers your cough. The doctor will scrape or prick your skin using a needle that contains a small amount of allergen extract. The allergen extract can come from different sources, such as pollen, pet dander, or dust mites. The allergist will observe the pricked areas for any reaction, such as swelling, itchiness, or redness.

The biggest drawbacks of the skin tests are that it can be uncomfortable and time-consuming. Skin pricks can be painful, and you will have to set aside some time to go to the allergist’s office. An at-home test will help you avoid all these inconveniences.

At-Home Allergy Test

If you want to save time and avoid the discomfort of a skin prick test, then an at-home allergy test is a good option. You can get an at-home allergy test from Wyndly by following these steps:

  1. Order the allergy test from Wyndly. We will ship our clinically-certified allergy tests to your door.
  2. Take an allergy test and send the results back to us. All you’ll need to do is draw a small blood sample through a finger prick. You will mail the sample back to us and wait for the results.
  3. Receive your personalized allergy profile. Our certified allergists will create your allergy profile based on the test results. They will also develop a personalized treatment plan based on your allergy triggers.

How to Treat an Allergy Reaction

There are several different ways to manage and treat your allergy symptoms. Some options offer temporary relief, while others can result in long-term relief from your symptoms. If you want to reduce your allergy symptoms, try the following. 

Limit Exposure

One of the easiest ways to combat watery eyes, coughing, and other common signs of allergies is to limit your exposure to the allergens that are causing your symptoms.

The following practices can help you avoid exposure and reduce your allergy reactions:

  • Check pollen counts: Before heading outdoors, take a glance at the local pollen count. If it's high, take extra care to protect yourself from exposure. Wearing a dust mask or sunglasses when outside can make a big difference in decreasing the amount of pollen you breathe in or that gets in your eyes.
  • Stay indoors when pollen counts are high: Pollen counts are usually highest in the morning and afternoon. If you are going to spend time outdoors, try to plan around when the pollen count is at its highest to reduce your exposure to your allergy triggers.
  • Avoid wearing shoes indoors: Wearing shoes inside your home after being outside can cause you to track pollen and other allergens into your home. Take your shoes off when you come inside to limit how much pollen you bring into your home with you.
  • Wipe your pets: If you have pets that spend time outdoors, wipe them down regularly with a damp towel to keep them from tracking allergens inside.
  • Clean regularly: Vacuum your home with a HEPA filter to capture pollen and other allergy triggers. This will help to prevent pollen, dust, and animal dander from building up.
  • Shower after being outside: Pollen can cling to your hair and skin after spending time outdoors. To avoid tracking it throughout your home, take a shower as soon as you come inside.
  • Do laundry more often: Pollen can also stick to your clothes after you’ve been outdoors. Cleaning your clothes more often will reduce the amount of pollen that builds up on your clothing or the amount of pollen your clothes bring inside.


While limiting exposure can reduce your allergy symptoms, certain allergy triggers, like pollen, are nearly impossible to fully avoid. Certain medications can help you temporarily manage your allergy symptoms.

  • Antihistamines: Antihistamines work by temporarily blocking histamine, a chemical that your body releases in response to an allergic trigger. This can help to relieve symptoms like itchiness, sneezing, and a runny nose. A popular antihistamine used for allergy reactions is Benadryl, but drowsiness is a common side effect. 
  • Eye drops: If your eyes are especially sensitive to pollen, using eye drops may provide some short-term relief.
  • Nasal sprays: Nasal sprays can help clear pollen and other allergens from your nasal passages. They can also help reduce inflammation and relieve congestion.

If OTC allergy medications aren't effective for you, or you are looking for long-term relief, sublingual immunotherapy might be right for you.

Sublingual Immunotherapy

Sublingual immunotherapy provides long-term relief from your allergies. Sublingual immunotherapy, also known as allergy drops or tablets, involves gradually introducing small doses of an allergen into the body. This gradual exposure retrains the immune system to ignore your allergy triggers instead of reacting.

Sublingual immunotherapy is as effective as allergy shots. However, there's no need to deal with painful injections or inconvenient, time-consuming doctor's appointments. You can safely take sublingual immunotherapy from the comfort of your home.

Take Our Allergy Assessment

If allergies are causing you discomfort, choose Wyndly. Our doctors will identify your allergy triggers and create a personalized treatment plan to get the care you need and live free from your allergies.

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