What is a severe allergy?

Allergies can affect people differently. While one person might have a mild reaction to a certain allergen, someone else might experience more severe symptoms. Mild allergies are an inconvenience, but severe allergies can be life-threatening.

The substances that cause allergies are called allergens. Although pollen, dust mites, and mold spores are common allergens, it’s rare for a person to have a severe allergy to them, because they’re everywhere in the environment.

Possible severe allergens include:

These foods cause the most allergic reactions:

Mild allergy symptoms may not be extreme, but they can affect the entire body. Mild symptoms may include:

Severe allergy symptoms are more extreme. Swelling caused by the allergic reaction can spread to the throat and lungs, leading to allergic asthma or a serious condition known as anaphylaxis.

Some childhood allergies can grow less severe over time. This is particularly true for egg allergy. However, most allergies last throughout life.

You can also develop allergies as a result of repeated exposure to a toxin, such as bee stings or poison oak. With enough cumulative exposures over a lifetime, your immune system can become hypersensitive to the toxin, giving you a severe allergy.

Allergy symptoms occur when your immune system overreacts to allergens in your body. Your immune system mistakenly believes that an allergen from a food, such as a peanut, is a harmful substance invading your body. The immune system releases chemicals, including histamine, to fight off the foreign invader.

When your immune system releases these chemicals, it causes your body to have an allergic reaction.

When the immune system overreacts, it can cause body parts to swell, particularly these:

If your lips and tongue swell too much, they can block your mouth and prevent you from speaking or breathing easily.

If your throat or airways also swell, it may cause additional problems such as:

Antihistamines and steroids can help bring the allergic reaction back under control.

Asthma occurs when the tiny structures in your lungs become inflamed, causing them to swell and restrict airflow. Because allergic reactions often cause swelling, they can trigger a form of asthma called allergic asthma.

Allergic asthma can be treated the same way as regular asthma: with a rescue inhaler, containing a solution such as albuterol (Accuneb). Albuterol makes your airways expand, allowing more air to flow into your lungs. However, inhalers aren’t effective in cases of anaphylaxis, because anaphylaxis closes off the throat, preventing the medication from reaching the lungs.

Anaphylaxis occurs when an allergic swelling gets so extreme that it causes your throat to close, preventing air from getting through. In anaphylaxis, your blood pressure can drop, and your pulse can become weak or thready. If the swelling restricts airflow for long enough, you can even fall unconscious.

If you think you’re starting to experience anaphylaxis, use an epinephrine (adrenaline) injector, such as EpiPen, Auvi-Q, or Adrenaclick. Epinephrine helps to open your airways, allowing you to breathe again.

If you have severe allergies, an allergist can evaluate your condition and help you manage your symptoms. They can run a series of tests to find out what you’re allergic to. They may give you an epinephrine injector to carry with you in case of anaphylaxis.

You can also work with an allergist to develop an anaphylaxis emergency care plan, which can help you track your symptoms and medication.

You may also want to wear an emergency medical bracelet, which can help inform emergency health workers of your condition.