Types & Symptoms Common Allergy Types and Symptoms

What is an allergy?

An allergy is a hypersensitivity immune response to normally harmless substances, such as pollens or foods. For most people, these substances—also called allergens—pose no problem. In allergic individuals, however, the immune system identifies them as a threat and produces an inappropriate (i.e., abnormal) response.1 Hundreds of ordinary substances may trigger an allergic reaction.

When someone is exposed to an allergen and he or she becomes sensitized, the body then produces antibodies called Immunoglobulin E (IgE). The next time the person encounters the same allergen, the allergen binds to the IgE antibodies and causes the mast cell to release histamine and other chemicals. This reaction causes inflammation and triggers allergy symptoms that can range from mild to severe, affecting the skin, gastrointestinal tract, cardiovascular system, and/or respiratory tract.

Common Allergy Symptoms

Mild and more common allergy symptoms include:4

  • Sneezing
  • Watery eyes
  • Runny nose
  • Wheezing
  • Coughing
  • Stomach pain
  • Hives
  • Itchy mouth or ears
  • Swelling of lips, tongue, or throat

For a full list of symptoms broken down by allergen type, explore the Allergen Fact Sheets


Anaphylaxis is a rare, but serious, life-threatening allergic reaction. Symptoms of anaphylaxis may include:

·   Loss of consciousness
·   A drop in blood pressure
·   Severe shortness of breath

Anyone experiencing anaphylaxis symptoms should call his or her local emergency number immediately.

A blood test—together with an allergy-focused medical history—may help identify underlying allergen triggers. 

The symptoms of allergic diseases are numerous and may also be attributable to more than one allergy, as up to 80 percent of allergic patients are sensitized to more than one allergen.5

Frequently Asked Questions

Anyone can be affected by allergies, but some people are more prone to them than others. Genetic and environmental factors play a role in a person's susceptibility to developing allergies. For children, allergies can develop for the first time at any point during their youth. It’s even possible some adults will develop allergies later in life.

Because allergies change over time, many people may outgrow old allergies and develop new ones. Some children stop reacting to allergens, such as milk and egg, as they grow, yet allergies to foods such as nuts and fish tend to remain. Allergy march, also called the allergic march or atopic march, is a specific way that allergy symptoms often progress in children.6

Everyone has his or her own unique combination of allergic triggers, and not all of them are obvious. For some, symptoms may appear only when they encounter two or more substances they’re allergic to at the same time. This is called the symptom threshold—the point where a person may start experiencing allergy symptoms when exposed to multiple allergic triggers. Learn more about the symptom threshold.

Common allergy symptoms in children include:7

Common allergy triggers in children include:7

In addition, one of the most common medical problems children face is middle ear infection, also called otitis media. Allergies may play a role in ear infections, as allergic inflammation can cause swelling and congestion in the middle ear and eustachian tube.

Cross-reactivity occurs when the body's immune system identifies the proteins in one substance (e.g., pollen) and the proteins in another (e.g., fruit and vegetables) as being similar. Meaning, someone with a pollen allergy may also experience an allergic-like reaction when eating some fruits. Learn more about cross-reactivity.

Are you a healthcare provider looking for practice parameters and guidelines?

Get clinical insights on:

Allergy Testing and Management

The mainstays of management in allergic conditions are exposure reduction and/or avoidance, thereby reducing the causative factor behind symptoms.

Identifying allergic triggers can help:

  • Control allergic asthma and allergic rhinitis.
  • Prevent the use of avoidable medications and reduce the number of office visits.
  • Optimize care and manage health risks.
  • Reduce costs associated with absenteeism and lost productivity at work and school.

A blood test—together with an allergy-focused medical history—may help identify underlying allergen triggers.

Tools for Understanding Allergies


Track allergy symptoms and prepare for a visit with a healthcare provider.

Learn about specific allergens, including common symptoms, management, and relief. 

Are you a healthcare provider? Get comprehensive information on hundreds of whole allergens and allergen components.

Related Content

Want to learn more about allergies? Explore a range of topics.

  1. Pawankar R, Holgate S, Canonica G, at el. World Allergy Organization. White Book on Allergy (WAO). 2011. http://www.worldallergy.org/UserFiles/file/WAO-White-Book-on-Allergy_web.pdf. Accessed December 2017.
  2. Allen-Ramney F, Schoenwetter W, Weiss T, et al. Sensitization to Common Allergens in Adults with Asthma. JABFP. 2005;(18)5 434-439.
  3. Host A, Halken S. Practical aspects of allergy-testing. Paediatr Respir Rev. 2003; (4) 312-318.
  4. Asthma and Allergy Foundation of America [Internet]. Arlington, VA: Asthma and Allergy Foundation of America; 2015 Nov. Available from: https://www.aafa.org/allergy-symptoms/. Accessed July 2019.
  5. Giorgio Ciprandi, Cristoforo Incorvaia & Franco FratiThe Italian Study Group on Polysensitization (2015) Management of polysensitized patient: from molecular diagnostics to biomolecular immunotherapy, Expert Review of Clinical Immunology, 11:9, 973-976, DOI: 10.1586/1744666X.2015.1062365.
  6. Spergel JM, Paller AS. Atopic dermatitis and the atopic march. J Allergy Clin Immunol. 2003;112 (6 Suppl):S118-27.American College of Allergy, Asthma & Immunology [Internet]. Arlington Heights, IL: American College of Allergy, Asthma & Immunology; 2021. Available from: https://acaai.org/allergies/allergies-101/who-gets-allergies/children/.
  7. American College of Allergy, Asthma & Immunology [Internet]. Arlington Heights, IL: American College of Allergy, Asthma & Immunology; 2021. Available from: https://acaai.org/allergies/allergies-101/who-gets-allergies/children.