Signs and Symptoms of Allergies

If you're one of the millions who have allergies, you might be aware of some common symptoms: sneezing, coughing, and itchy eyes—not to mention the fatigue that can come along with them.  

Allergies are caused by the body's immune system mistaking a normally harmless substance as something dangerous, causing an unnecessary reaction. The substance that causes the reaction is called an allergen. Common allergens include latex, pollen, pet dander, mold, dust mites, insect venom, as well as certain foods, plants, and medications.

Common Symptoms

Allergies can be difficult to identify because they can have a variety of symptoms. However, some symptoms are common across different allergens, including:

  • Sneezing
  • Coughing
  • Runny nose
  • Sore throat

In serious cases, allergies can cause hives, rashes, and trouble breathing. If not treated promptly, severe allergic reactions can lead to anaphylaxis, a potentially life-threatening condition. 

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Symptoms by Allergen Type

Some symptoms of allergies can be characteristic of the type of allergen that’s triggering the reaction.

Food Allergy Symptoms

Food allergies are most common in children, but adults can have them too. It’s important to know the signs of a food allergy so you can take steps to stay safe. 

Allergies to certain foods tend to run in families. For instance, if a child has a peanut allergy, their younger siblings are likely to be allergic to peanuts as well. However, you cannot always predict if you or your child will have an allergy.

Any food can cause an allergy. However, 90% of all food allergies come from the following types of food:

  • Peanuts
  • Cow milk and other dairy products
  • Eggs
  • Tree nuts (such as almonds, cashews, pecans, pistachios, walnuts, hazelnuts, and Brazil nuts)
  • Fish
  • Shellfish (most commonly, crustaceans like shrimp, lobster, and crab, and less commonly, mollusks like scallops, oysters, clams, and mussels)
  • Soy
  • Wheat
  • Sesame

Food allergy reactions can affect the gut, heart and blood vessels, lungs, or skin. Common symptoms include:

  • Stomach cramps
  • Vomiting
  • Frequent cough
  • A swollen tongue
  • Wheezing (a whistling sound when breathing)
  • Hives (urticaria), a rash characterized by itchy bumps called wheals

These are not all the symptoms that can occur. Most reactions occur within two hours of ingestion. Many times, the reaction occurs within minutes. Everyone’s reaction to a food allergy is different. If you think you or your child may have a food allergy, it’s important to see an allergist (a doctor who specializes in allergic conditions) for proper diagnosis and treatment. 

Environmental Allergy Symptoms

Allergens that arise from our everyday surroundings can cause environmental allergies. They include things like:

  • Pollen: Grass, trees, and weeds produce pollen, which can circulate in the air at varying levels throughout the seasons.
  • Mold: While not all types of mold can lead to allergy, some people may be allergic to certain molds found in damp indoor places such as basements, bathrooms, and around windows. Common types of mold that could trigger an allergy include Alternaria, Aspergillus, Cladosporium, and Penicillium. 
  • Animal dander: This is made up of dead skin cells found in fur or feathers. Household pets like cats or dogs can be a common source of dander, though washing your pet, reducing contact, and washing your hands after petting them can help reduce allergic symptoms.
  • Dust mites: These are microscopic bugs that live in dust. The fecal matter of dust mites contains a type of digestive protein called peptidase 1, which is the main allergen. Dust mites can travel through indoor air and trigger an allergy.
  • Cockroaches: These insects thrive in damp, dark places with food waste. Cockroach feces is the main allergen that can lead to allergies. Keeping an indoor space free of excess moisture and uncovered food can reduce cockroach infestations, along with hiring an exterminator if needed.

If you have an allergy to one of these, you will likely have common allergy symptoms. However, some people may also have:

  • Rash
  • Nasal and sinus congestion
  • Watery or burning eyes
  • Itchiness in the nose, mouth, or throat
  • Mucus in the throat, particularly for mold allergies

Latex Allergy Symptoms

Latex, also called natural rubber latex, is a flexible material that is made from the sap of rubber trees, known as Hevea brasiliensis. Some gloves, bandages, and other items may be made from latex. A latex allergy can be triggered by certain proteins in natural rubber.

An allergic reaction can happen when latex makes direct contact with your skin, is inhaled from latex particles in the air, or comes into contact with mucus membranes, like your mouth or eyes. People with allergies to latex can either have an immediate reaction or a delayed skin reaction.

Common latex allergy symptoms usually include:

  • Red, swollen lips after blowing up a balloon
  • Itchy or swollen skin after contact with a latex bandage, gloves, condom, or vaginal diaphragm 
  • Itching or swelling of your mouth or tongue after a dental exam involving latex gloves

Severe allergic reactions to latex can cause additional symptoms such as:

  • Hives (urticaria)
  • Runny nose and sneezing
  • Red, swollen, pain, or blurry vision in the eyes (eye inflammation)
  • Trouble breathing

Using products labeled as “not made with natural rubber latex” can help reduce the likelihood of latex allergies.

Insect Allergy Symptoms

Insect allergies can cause a range of symptoms, depending on the severity of the allergic reaction and type of insect. For example, insect stings contain venom, which can trigger an allergy in some people. Common culprits of insect sting allergies are bees, wasps, hornets, and fire ants. Other allergies can be triggered by insect bites, such as mosquitoes, bed bugs, fleas, and more.

Insect bites or stings can cause common symptoms like pain, stinging, redness, and mild swelling around the affected area. 

If you are seriously allergic to stings or bites, you might experience more severe symptoms such as difficulty breathing, swelling, and nausea. Severe symptoms are typically more common after insect stings and considered rare for insect bites.

Medication Allergy Symptoms

Antibiotics, or drugs used to treat bacterial and fungal infections, are among the most common drugs reported with drug allergies. But only about 2% of reported drug allergies at hospitals tend to be allergic reactions, as some people might experience side effects from a drug or complications from a current infection.

Penicillin, a type of antibiotic, is one of the most widely reported drug allergies, with up to 10% of people claiming they’re allergic. However, when tested for penicillin allergy, less than 1% of the general population actually turns out to be allergic.

Like other allergic reactions, medication allergies can range from mild to severe and life-threatening. Some symptoms may include:

  • Rashes
  • Hives
  • Swollen eyes or lips
  • Itching
  • Coughing
  • Trouble breathing
  • Belly pain
  • Diarrhea
  • Vomiting

Serious and Life-Threatening Symptoms

Allergies can be very serious and even life-threatening in some cases. Anaphylaxis is a severe and potentially life-threatening allergic reaction that can affect several organs in your body. Symptoms can develop quickly and may include:

  • Difficulty breathing
  • Wheezing
  • Swelling of the face, tongue, and throat
  • Dizziness
  • Faintness
  • Nausea
  • Hives

If You Have a Severe Allergic Reaction

If you are experiencing anaphylaxis, get help right away by calling 911. Anaphylaxis needs to be treated promptly with a shot of epinephrine—a hormone that’s also called adrenaline. This treatment is highly effective at slowing or stopping an allergic reaction and can be life-saving.

Even if you use epinephrine, you still need to seek immediate medical care.


If you have a history of allergies, talk to your healthcare provider about getting epinephrine auto-injectors. Allergens that more commonly lead to anaphylaxis include peanuts, tree nuts, fish, crustacean shellfish (such as shrimp, lobster, or crab), fish, insect stings, and latex.

Even if you have a history of mild allergic reactions, you can still be at risk of anaphylaxis. If you have a history of severe allergic reactions to a known allergen, you are at high risk of anaphylaxis. Your provider can show you how to administer an epinephrine auto-injector in case of an emergency.


Single-use shots of epinephrine are called auto-injectors, which can be self-administered or administered by someone else. A common brand is EpiPen. People with a history of allergies should carry two epinephrine auto-injectors with them in case of an emergency.  Epinephrine works by rapidly:

  • Increasing low blood pressure
  • Improving breathing
  • Decreasing swelling

When to See a Healthcare Provider

You might be tempted to self-diagnose your allergy symptoms, but it is important that you see an allergist if you have any concerns. Allergists know how to best diagnose and treat allergies and can provide you with better insight into the root cause of your symptoms.

If your allergies are not getting better or if they are getting worse, you should ask a healthcare provider for help. Also, if you have sudden symptoms you can't explain, or if your symptoms last more than a week, call your primary care provider or allergist for a diagnosis and treatment plan.

A Quick Review

Allergies are the reaction of your body's immune system to an otherwise harmless substance. Common symptoms may include red and itchy eyes, sneezing, coughing, runny nose, and skin rashes. More severe reactions such as difficulty breathing, tightness in the throat or chest, and fainting require immediate care.

If you experience any of these signs or symptoms after contact with a particular food, animal, pollen, or other substance, see your healthcare provider right away for a proper diagnosis.

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