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Allergy Types & Causes

An allergy is when your body’s immune system reacts to something that’s normally harmless to most people. If you come into contact with a substance (allergen) that your immune system views as a threat, it responds by releasing a chemical called histamine. The release of histamine is what causes the reactions you feel, and where you experience the reaction depends on where histamine was released in your body. For example, if you’re allergic to something you breathe in—like pollen, dust mites, animal dander or mold—your nose, lungs and eyes could be where you are most likely to have symptoms. If you’re allergic to any food, you may experience symptoms in your mouth or digestive system.

anything you come into contact with (allergens) could cause an allergic reaction infographic

Allergy types include: 

Allergies exist in several different forms, but many fall into larger buckets like seasonal, year-round, food or bee, wasp, and hornet allergies.

Year-Round Allergies

Year-Round Allergies

If you’re always sniffling and sneezing, this may be why.

Year-Round Allergies

Seasonal Allergies

Seasonal Allergies

The frequent cause of your spring or fall sneezes.

Seasonal Allergies

Food Allergies

Food Allergies

More than 170 foods can cause allergic reactions.1

Food Allergies

Hornet, Wasp & Bee Sting Allergy

Hornet, Wasp & Bee Sting Allergy

Get the buzz on the stinging insects behind this allergy.

Hornet, Wasp & Bee Sting Allergy

Common allergens

Spicy food can make your nose run, and a bug bite can be annoyingly itchy. Most people experience reactions like these from time to time. These reactions are usually sensitivities or intolerances, but they could also be related to allergies. Anything you come into contact with (allergens) could cause an allergic reaction if your immune system views it as a threat and responds by releasing histamine, along with other substances released by the body.

Certain substances are frequently responsible for allergic reactions. Some of the most common types of allergies include the below:

Your cat or dog could be causing your symptoms.

These tiny creatures cause many allergic symptoms.

Endless sniffles could actually be a reaction to insects.

An allergic reaction to this fungus is no fun at all.

A variety of grasses can make you sneeze.

Some trees are big pollen producers.

Ragweed pollen is a cause of an itchy nose.

Egg is a major cause of reactions in infants.6

Milk allergy is not the same as lactose intolerance.

Peanut is a major cause of severe reactions.2

Tree nuts can cause severe allergic reactions.8,9

A shellfish allergy isn't the same as fish allergy.

Fruit and vegetable allergy symptoms are usually digestive.

This is a common food allergen for young children.10

This allergy is not the same as gluten intolerance.

  2. Du Toit G, Roberts G, Sayre P, et al. Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy. New Eng J Med. 2015; 1-11.
  4. Lifschitz C, Szajewska H. Cow’s milk allergy: evidence-based diagnosis and management for the practitioner.  Eur J Pediatr 2015; 174:141-15.
  5. Caubet J, Wang J. Current understanding of egg allergy. Pediatr Clin North Am. 2011 Apr 1; 58(2): 427–443.
  6. Gupta RS, Springston EE, Warrier MR, et al. The prevalence, severity, and distribution of childhood food allergy in the United States. Pediatrics 2011;128:e9-17. (III).