Allergy Symptoms: Common Causes and Early Signs to Look For

Published August 9th, 2021 by Chris Riley
Fact Checked by
Camille Freking
Medically Reviewed:
Dr. Angel Rivera

An estimated 20 percent of Americans have some type of allergy, making it one of the most common afflictions in the United States. People can be allergic to just about anything, including pollen, animal dander, mold spores, foods, medications, insect bites or stings, latex, and more, and the symptoms people experience vary widely depending on the cause of the reaction.

While many people are familiar with the itchy, watery eyes, sneezing, and nasal congestion associated with seasonal allergies and pollen, the symptoms associated with other types of allergies are less widely known.

If you think you might be experiencing allergy symptoms, here are some common causes and early signs to look for.

What Are Allergies?

Allergies are one of the most common causes of chronic illness in the United States, affecting more than 50 million Americans. Despite being extremely common, not everyone is familiar with the common symptoms of allergies, as the type of symptoms a person experiences varies depending on their unique physiology, the allergen, and the amount of exposure.

A person is said to have allergies when their immune system experiences a defensive reaction to a foreign substance, known as an allergen, that would otherwise be considered harmless in most people. There are many different types of allergens, but the most common include medicines, food, insect bites or stings, and environmental allergens like pollen or dust mites. 

Common allergens include:

  • Medications
  • Stings from insects, such as bees, fire ants, or wasps
  • Bites from insects, such as mosquitos or ticks
  • Household pests, such as cockroaches or dust mites
  • Mold
  • Pollen
  • Certain foods, like peanuts
  • Latex
  • Pet urine, saliva, or dander

People may experience allergies on a seasonal basis, which is common with certain types of environmental allergens, such as mold or pollen from trees, grass, and weeds. They may also experience allergies year-round, which are referred to as perennial allergies. It is possible for a person to have both seasonal allergies and perennial allergies.

What Happens During an Allergic Reaction?

An allergic reaction starts with exposure to an allergen. This exposure can occur in a wide variety of ways, from eating a food that contains an allergen to using a medication with an ingredient that the individual is allergic to. Breathing air that contains a certain type of pollen or using certain types of detergent to wash clothes can also provoke an allergic reaction.

Once a person is exposed to an allergen, their immune system begins to mount a defensive response and produces an antibody known as immunoglobulin E (IgE). These antibodies try to attack and remove the allergen from the body, leading to the symptoms associated with an allergic reaction.

What Symptoms Are Commonly Associated With Allergies?

The types of symptoms that a person experiences during an allergic reaction vary from person to person and depend on the allergen the person is exposed to. Symptoms of allergies are typically grouped into indoor/outdoor allergies, skin allergies, food allergies, drug allergies, and insect allergies.

Indoor/Outdoor Allergies

Indoor/outdoor allergies are allergies associated with exposure to environmental allergens such as different types of pollen, dust mites, mold spores, cockroaches, or animal dander.

The symptoms associated with these allergens commonly affect the nasal passages and eyes and begin when a person breathes in air containing particles of the allergen. Allergy symptoms commonly associated with indoor/outdoor allergies are often grouped together under the term allergic rhinitis, or hay fever, and the condition affects more than 24 million adults in the United States. 

Symptoms commonly associated with allergic rhinitis include:

  • Itchy, watery eyes
  • Runny or stuffy nose
  • Sneezing
  • Nasal congestion

Other symptoms may or may not occur with allergic rhinitis, including:

  • Fatigue
  • Cough
  • Sore throat

Skin Allergies

Skin allergy symptoms occur when an allergen makes contact with the skin. There are many different ways that this can occur, such as wearing a piece of clothing washed in a detergent that contains allergens, coming in contact with poison ivy or poison oak, being touched with latex gloves during a doctor’s visit, and more. 

The most common symptoms of skin allergies include:

  • Skin inflammation
  • Hives
  • Itching or burning
  • Rash

People with skin allergies may need to use products produced specifically for people with very sensitive skin that do not contain irritating dyes or fragrances. These products are often labeled as hypoallergenic and may help reduce the risk of allergic reactions in sensitive people.

Food Allergies

Food allergies are extremely common and are growing in prevalence in the United States. An estimated 32 million people in the United states have food allergies.

Although it is possible for people to be allergic to any food, there are eight foods that cause the vast majority of allergic reactions, including milk, soy, eggs, wheat, peanuts, tree nuts, fish, and shellfish. 

The symptoms associated with food allergies vary from person to person and can range in severity from uncomfortable to life threatening. Symptoms typically develop shortly after ingesting a food that contains an allergen, but may take up to two hours to develop.

The most common symptoms associated with food allergies include:

  • Itching or tingling of the mouth
  • Difficulty breathing, nasal congestion, or wheezing
  • Dizziness, fainting, or lightheadedness
  • Skin reactions such as itching, eczema, or hives
  • Abdominal distress, such as pain, nausea, vomiting, or diarrhea

Food allergies can trigger a life threatening, severe form of allergic reaction known as anaphylaxis. People experiencing anaphylaxis must seek emergency medical attention right away. 

Symptoms of anaphylaxis include:

  • Swelling in the throat that makes it difficult to breath
  • Narrowing or constriction of the airways
  • Rapid pulse
  • Lightheadedness, dizziness, or loss of consciousness
  • Severe drop in blood pressure accompanied by shock, known as anaphylactic shock

Drug Allergies

Drug allergies occur when the body has an allergic response to an ingredient in a particular medication. People can be allergic to any type of medication, but some medications are more likely to cause allergic reactions than others, including antibiotics. 

The most common symptoms associated with drug allergies include:

  • Skin rash
  • Itching
  • Swelling
  • Wheezing
  • Itchy, watery eyes
  • Hives
  • Fever
  • Shortness of breath
  • Runny nose

Like food allergies, drug allergies can cause a life threatening, severe form of allergic reaction known as anaphylaxis. People experiencing anaphylaxis must seek emergency medical attention right away. 

Symptoms of anaphylaxis include:

  • Swelling in the throat that makes it difficult to breath
  • Narrowing or constriction of the airways
  • Rapid pulse
  • Lightheadedness, dizziness, or loss of consciousness
  • Severe drop in blood pressure accompanied by shock, known as anaphylactic shock

Drug allergies may also cause allergic reactions that occur days or weeks after the individual has been exposed to the medication.  

These conditions include:

  • Serum sickness
  • Drug rash with eosinophilia and systemic symptoms (DRESS)
  • Drug-induced anemia
  • Inflammation of the kidneys (nephritis)

Insect Allergies

Allergies to insect bites or stings are also common. When an insect such as a bee, hornet, wasp, yellow-jacket, or fire ant stings you, it injects a small amount of toxic venom into your bloodstream.

While most people will experience some pain, stinging, and mild discomfort, people with an allergy to the venom may experience a life-threatening allergic reaction. Insects that bite, such as mosquitos, bedbugs, fleas, flies, and kissing bugs, can also cause an allergic reaction.

Symptoms associated with insect allergies include:

  • Pain in the vicinity of the sting or bite 
  • Swelling in the vicinity of the sting or bite and beyond
  • Hives
  • Redness
  • Flushing
  • Itching

Like food allergies and drug allergies, insect allergies can cause a life threatening, severe form of allergic reaction known as anaphylaxis. People experiencing anaphylaxis must seek emergency medical attention right away.

Symptoms of anaphylaxis include:

  • Swelling in the throat that makes it difficult to breath
  • Narrowing or constriction of the airways
  • Rapid pulse
  • Lightheadedness, dizziness, or loss of consciousness
  • Severe drop in blood pressure accompanied by shock, known as anaphylactic shock

Summary

Allergy symptoms vary depending on the cause of the allergic reaction. Whether a person is allergic to a certain type of food, pollen, mold spores, pet dander, latex, medications, or insect bites or stings, their reaction is likely to include certain common symptoms.

Indoor/outdoor allergies are likely to cause symptoms such as nasal congestion, itchy/watery eyes, sneezing, and a runny or stuffy nose.

Skin allergies may cause symptoms such as skin inflammation, hives, itching or burning, and a rash.

Food allergies are likely to cause symptoms like itching or tingling of the mouth; difficulty breathing, nasal congestion, or wheezing; dizziness, fainting, or lightheadedness; skin reactions such as itching, or hives; and abdominal distress, such as pain, nausea, vomiting, or diarrhea. Some people may also experience a severe type of allergic reaction known as anaphylaxis.

Drug allergies may cause symptoms like skin rash, itching, swelling, wheezing, itchy/watery eyes, hives, fever, shortness of breath, and runny nose. Some people may also experience a severe type of allergic reaction known as anaphylaxis.

Insect allergies are likely to cause symptoms like pain in the vicinity of the sting or bite, swelling in the vicinity of the sting or bite and beyond, hives, redness, flushing, and itching.

Some people may also experience a severe type of allergic reaction known as anaphylaxis.

Sources:

Allergy Facts | Asthma and Allergy Foundation of America 

Food allergy - Symptoms and causes | Mayo Clinic 

Drug allergy - Symptoms and causes | Mayo Clinic 

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