What Are Allergies?


Do you avoid eating a particular food? Do you sneeze and have a runny nose when being in close contact with cats' fur? These body symptoms happen as a reaction to something that is normally harmless like pollen, pets’ fur, or dust. This reaction is called an allergy. 

Its symptoms can be mild but they can escalate and become serious with some people. This article will provide you with information about the types of allergies, their causes, and ways to manage and treat them.

Common types of allergies

There are many types of allergies, including 

  • Food allergies 
  • Seasonal allergies 
  • Skin allergies 

Food allergy 

Food allergies occur when the immune system reacts to a specific food, such as peanuts, dairy products, seafood etc. It can happen even if you are in contact with a tiny amount of food. It is now a major public health burden in developed countries. It can happen to both children and adults alike. There is nine common food that can be allergens like 

  • Cow’s milk 
  • Eggs 
  • Fish 
  • Peanut 
  • Soy 
  • Sesame 
  • Shellfish 
  • Wheat
  • Tree nuts 

Symptoms of food allergy 

The symptoms of food allergy include disturbance to the skin, and gastrointestinal tract, and cardiovascular aberration (irregularity in the rhythm of the heartbeat). Many patients outgrow it over time which means they will have little to no reaction to the food, however, it depends on the causative food allergens. For example, peanut allergies persist for life whereas hen egg allergy is frequently outgrown. 1 

Seasonal allergy

Seasonal allergies, also known as hay fever (allergic rhinitis), occur when the immune system overreacts to pollen, mould, or other airborne allergens. It is prevalent and affects 1 in 5 people in their life. If you have an allergy to pollen you may experience hay fever. Pollen is released by plants as a part of their reproductive cycle. It is seasonal because, during spring,  you can have an allergy to tree pollen. During the end of spring and the beginning of summer, you can have an allergy to grass pollen. During late autumn, you can have an allergy to weed pollen. 

Symptoms of seasonal allergy 

Some common symptoms experienced are stuffy or runny nose, sneezing, itchy eyes and nose, sore throat and cough etc. These symptoms may improve as they grow older. 

Skin allergy 

Skin allergies can be caused by contact with certain substances, such as latex or nickel. 

Symptoms of skin allergy 

The common symptoms of skin allergies are itchy, red, or dry skin. There are some differences in the symptoms that help in the diagnosis of certain skin allergies like Hives and Eczema.

Causes of allergies

Allergies can be caused by various agents and these agents are called asallergens. The common allergens are pollen, dust mites, food like peanuts, animal furs like cats and dogs, insects, and certain medication side effects. Allergy cases usually run in families. There is a tendency of having a certain allergy if other members of your family have it. Developing an allergy depends on various factors including environmental factors. For instance, people who are exposed to air pollution and dust are likely to develop allergies and asthma.

The immune system of the body reacts to certain foreign proteins—allergens—that, for the most part, do not cause any harm. It treats them like foreign bodies or germs. For example, even though dust, vermin and food varieties have no issues in the body in most cases, they trigger a response in individuals who are hypersensitive to them. Because the body of the hypersensitive individuals considers these substances to be harmful and the immune system produces antibodies (IgE antibodies) to combat them. 

When the body first encounters the allergen, IgE antibodies for that particular allergen are produced and they get attached to specific types of cells. This process is known as "Sensitization". These cells release chemical substances, including histamines, whenever the body comes back into contact with the allergen. The allergic reactions that result from these substances are sneezing, coughing, and skin rashes.

Management and treatment for allergies

Treating and managing allergies are based on the medical history and the severity of the symptoms. The common three ways of treatment are:2 

  • Avoidance of allergens 
  • Medication 
  • Immunotherapy 

The effectiveness of avoiding allergens depends on the type of allergen. For example, it is easy to avoid food and chemical allergens whereas it is impossible to avoid pollen completely. You can avoid pollen to an extent by following pollen calendars and forecasts. Also, people with dust mite allergies can avoid exposure or take precautions like dust traps. Medications like antihistamines or steroids are often used. They are used mainly for allergic rhinitis and conjunctivitis. You can get these medications in the form of tablets, nasal sprays, and injections. For skin allergic reactions, you can get steroid lotions and creams. Desensitization is another form of treatment that is allergen-specific immunotherapy. It is done by injecting allergens under the skin or the tongue as drops or tablets. This immunotherapy can take about three to five years and is mainly used for treating hay fever, dust mites, or insect venom.


Can allergies be prevented?

Avoiding allergens is the best way to prevent allergies. You should always have an allergy action plan because it is not always possible to avoid allergens especially outdoor allergens like bees and other insects that cause allergies. It is a good idea to carry your medication with you if you are stung so you can treat an allergic reaction. Do not worry about allergies interfering with your daily life and your activities at school even at home. People experiencing allergies live a normal life. You should see your GP to get guidance on the treatment and follow the steps to avoid your allergy.

How do I test for allergies?

You should visit a doctor and they can arrange an allergy test for you. The types of test you might have to take are patch test or skin prick where the GP puts a small amount of allergen on your skin to check whether it reacts, followed by a blood test to check for allergens triggering the symptoms, or following a special diet to check if the allergy symptoms get better when you avoid eating a certain food.

How common are allergies?

Allergies are considered one of the most common chronic conditions worldwide. 

Are allergies contagious?

Allergies are not contagious but can bother you and it is important to know how to manage them.

What can I expect if I have allergies?

If you have allergies, you can expect to experience a runny nose, sneezing, pain around your cheeks, coughing, wheezing, breathlessness, diarrhoea, and feeling pain or tenderness around your cheeks, forehead or eyes.

When should I see a doctor?

You should see a doctor if you experience wheezing which may indicate a blockage in your airway. When you feel tightness in the throat or chest or you have trouble breathing or talking. You notice swelling in your face, mouth, throat, or lips. There is a possibility that you are having anaphylaxis which is a severe life-threatening allergic reaction with rapid development.


Allergies are a common health problem that can significantly affect an individual's quality of life. Understanding the causes, symptoms, types, management, and prevention of allergies can help individuals reduce their exposure to allergens and manage their symptoms effectively. More research is needed to develop new treatments and preventions for allergies, but with proper management, people with allergies can live healthy and productive lives.


  1. Renz H, Allen KJ, Sicherer SH, Sampson HA, Lack G, Beyer K, Oettgen HC. Food allergy. Nature reviews Disease primers. 2018 Jan 4;4(1):1-20. Available From: https://pubmed.ncbi.nlm.nih.gov/29300005/ 
  2. Allergies: overview [Internet]. Institute for Quality and Efficiency in Health Care (IQWiG); 2020 [cited 2023 Aug 14]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK447112/ 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Aamal Alshihawi

Bachelor of Science in Public Health, Asian University for Women, Bangladesh

Aamal is a public health practitioner with experience in research and management roles in the NGO sector. She has two years of experience in health promotion, mental health, and research. Also, she works in the education sector and has over two years of experience in curriculum content development and design. She is working now as an internship coordinator.

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