What Are Severe Allergies?

Definition, Causes, Treatment, and Coping

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Allergies are one of the most widespread diseases in the modern world. More than 25% of the population in industrialized countries suffers from allergies.

There are many types of allergic diseases, including asthma, atopic dermatitis (AD), allergic rhinitis (AR), conjunctivitis, chronic rhinosinusitis (CRS), and food allergies. The onset and rise in allergic cases have known to be caused by pollution, weather, climate change, lifestyle and dietary habits, and, in some cases, they are hereditary.

While mild allergies are a problem, severe allergies are potentially life-threatening. The very same allergen might cause a slight reaction in one person and trigger severe allergies in someone else.

Woman Blowing Nose on Tissue Paper

Ian Hooton / Getty Images


Mild and severe allergies differ based on the severity of the symptoms. Common symptoms of seasonal allergies and hay fever, which are generally mild, include:

  • Sneezing
  • Runny nose
  • Nasal congestion
  • Itchy eyes
  • Skin rash
  • Hives

Common symptoms of severe allergies include:

  • Difficulty breathing
  • Swelling in throat or lungs
  • Anaphylactic reaction
  • Severe allergy rash
  • Death


Allergens are certain substances that cause an abnormal response of the immune system. 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 overreact. It may produce antibodies that attack the allergen.

People can develop allergies when they are exposed to allergens, although sometimes allergies form without known prior exposure. Some people may even grow out of them. However, it is rare for people to have severe allergies compared to common allergies.


Examples of common allergens and severe allergens may include:

More Likely To Cause Mild or Moderate Symptoms
  • Tree pollen

  • Molds

  • Mildew

  • Dust mites

  • Pets

Allergens That May Be Severe in Some People
  • Insect stings (e.g. bees)

  • Food allergies (e.g. peanuts, tree nuts, shellfish, eggs, fish, milk, wheat, soy)

  • Medication (e.g. penicillin)

  • Latex

Allergies range in severity, sometimes causing only mild symptoms, and sometimes resulting in a potentially fatal reaction called anaphylaxis.

Treating Severe Allergies

Just as the symptoms of allergies vary greatly, so do the treatments. The level of treatment changes based on the severity of symptoms.

To treat severe allergies, observe the lips and tongue for possible swelling. Be sure to monitor the ability to talk. In addition, look for shortness of breath, wheezing, or trouble breathing and swallowing. An overreacting immune system causes breathing difficulties secondary to swelling. Medications to treat severe allergies include:

  • Epinephrine: This life-saving medication is given when a person has a life-threatening allergy. Patients who have a life-threatening allergy to a food or stinging insect should obtain an epinephrine auto-injector after evaluation with a physician and carry one of these at all times to use in the event of anaphylaxis.
Obstructed Airways
Normal Bronchial Airway (left) vs. Obstructed Bronchial Airway (right).



Anaphylaxis is a severe, hypersensitivity reaction that is rapid and life-threatening. It can cause airway obstruction, breathing difficulties, circulatory problems, and accumulation of mucus in the lungs. Anaphylaxis is usually caused by traces of allergens that enter the body. If the condition progresses to anaphylactic shock, it can be fatal.

In medicine, anaphylactic shock has a very specific meaning. It refers to the organs in the body that are not getting enough blood because of dangerously low blood pressure. Shock may lead rapidly to death. It may also give a person a pale look.

To treat anaphylaxis, an epinephrine injector, such as an EpiPen, is used. Injection with an Epipen is usually done via intramuscular injection in the thigh region. Epipens are life-saving, but remember to seek medical attention after using a prescribed epinephrine auto-injector to treat anaphylaxis. The reason is some patients require additional doses and/or additional medical care after they have had an allergic reaction severe enough to require epinephrine use.

Coping With Severe Allergies

With any severe allergies, there are ways to cope with them to live a normal and healthy life. These include:

  • Avoiding known triggers
  • Tracking allergies with an app or a diary
  • Wearing an alert bracelet
  • Managing pet dander and dust mites in the home. You can do this by regularly cleaning your home, installing HEPA or HVAC filters, and keeping pets away from places in your home where you spend the most time.
  • Seeing a specialist like an allergist

A Word from Verywell

While severe allergies can be challenging to manage, it is important to recognize and understand their warning signs to manage your quality of health. Always consult with an allergy specialist to stay up-to-date on allergy prevention strategies and explore novel treatment options. These professionals have the advanced training and experience to create a personal management plan that can help you live a life as normal and healthy as possible.

Frequently Asked Questions

  • Why are some peanut allergies so severe?

    Scientists don’t know exactly why some peanut allergies are so severe or why their reaction time is so fast. One possible reason may be that peanut proteins, which are what cause a peanut allergy reaction, aren’t easily destroyed in the gut. This makes it easy for peanut proteins to enter the bloodstream and trigger a strong immune response.

  • Do allergies reduce life expectancy?

    While allergies can disrupt a person's daily activities, there is currently no evidence to suggest that mild or severe allergies reduce life expectancy when properly managed and treated. In fact, clinical studies show that fatal outcomes with anaphylaxis remain rare and account for less than 1% total mortality risk due to timely treatment of medication. However, risk factors for higher mortality include old age and underlying health conditions, such as heart disease.

  • What are the most common allergies?

    The most common allergies include pollen, dust mites, animal dander, food, insect bites and stings, medicines, latex, mold, and household chemicals.

  • How do I know what I'm allergic to?

    If you are concerned about an allergy, your physician will review your history with you and order any required testing. Blood and skin tests are both available, but neither is specific to allergy, meaning that some people have elevated values even when they can tolerate a specific allergen. Talk with your allergist about any testing that may be helpful and how to interpret results as they relate to your history.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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