Difference Between Asthma and Allergies

Asthma and allergies are both conditions that can affect the respiratory system, but they are fundamentally different. While both asthma and allergies can cause similar symptoms, such as coughing, wheezing, and shortness of breath, their causes and treatments differ significantly.

What is Asthma?

Asthma is a condition in which the airways become inflamed causing the bronchial tubes to constrict. Excess mucus is also often produced and the person struggles to breathe. Asthma should be taken seriously as it can kill a person if not controlled.

  • Symptoms of Asthma − Symptoms of asthma include a feeling of tightness in the chest, cough, and difficulty breathing. Patients often have wheezing and a slight drop in systolic blood pressure when breathing in (usually the decrease in blood pressure is about 10 mmHg). Breathing rate and heart rate often speed up. Some patients have worse asthma symptoms at night.

  • Diagnosis − The diagnosis is made based on both a physical exam and tests of lung function. The lung function tests include spirometry to see if airflow is restricted. Provocative testing is also sometimes done in which patients inhale a substance like histamine, and the amount of bronchoconstriction is then noted. In addition, diffusing capacity for carbon monoxide (DLco) tests and allergy tests may also be done.

  • Causes and Risk Factors − Asthma can be caused by an immune system response to allergens such as mold, dander, or pet dander. Other irritants such as cigarette smoke or perfumes can also worsen asthma. In some people asthma is triggered by exercise. Respiratory infections and some medicines such as aspirin or ibuprofen can also trigger an asthmatic attack in some people. Asthma occurs more often in boys and is more prevalent in cities than in rural areas, and it is more common in developed nations. More than 50% of first time attacks occur in childhood. Individuals who are prone to asthmatic attacks are more likely to have worse symptoms if they contract a respiratory infection.

  • Prevention and Treatment − Asthma attacks can be prevented by knowing what factors trigger the attacks for a person, and avoiding these triggers. Using HEPA filters in houses can help reduce the number of airborne irritants that may cause an allergic response and an asthma attack. Inhalers that contain beta-2 antagonists can help to relax and open up the airways. Corticosteroids, mast cell stabilizers and leukotriene modifiers can help with the inflammation as well

What are Allergies?

An allergy is an unusual and generally unpleasant response by the immune system to some substance that you are exposed to. There are several types of allergies that can occur including allergies to chemical substances that you eat, touch or breathe in. These are food, contact and respiratory allergies. In some people, allergies can resolve over time or can worsen. Stings from insects such as bees and wasps can also cause an allergic response.

  • Symptoms − Symptoms depend on the type of allergy that you have. For instance, the symptoms of a food allergy can include gastric upset, hives and in severe cases swelling causing you to stop breathing. Respiratory allergies can cause a runny or congested nose, sneezing, watery and itching eyes and rhinitis (inflamed nasal membranes). Contact allergies can cause a rash, itching, and hives.

  • Diagnosis − Allergies can be diagnosed by using blood tests and skin prick tests. Blood tests can show the presence of large amounts of immunoglobulin which is released when there is an allergic response. The skin prick test is done by pricking the skin lightly and introducing a small amount of the allergen you are suspected of being allergic to. If you are allergic you will develop a red raised and itchy bump known as a wheal.

  • Causes − Allergies are caused by exposure to allergens; chemicals in the environment that can trigger an abnormal immune response. Allergies do not occur in everybody but when they do occur it is because the person has an unusual and extreme immune response to a chemical.

  • Risk factors and complications − Having a family history of allergies and asthma is a risk factor for developing allergies. Allergies are also more common in children. Complications can include anaphylaxis which is a very dangerous and life-threatening reaction that can kill you.

  • Prevention and treatment for allergies − You can prevent allergies by avoiding the substances that trigger the reaction. Allergies can be treated using antihistamine medications and in severe cases, a person may need to carry an EpiPen on them. An EpiPen is an injectable epinephrine that you can administer during a severe allergic reaction to reverse anaphylaxis.

Differences Asthma and Allergies

One of the key differences between asthma and allergies is that asthma can be life-threatening, while allergies typically are not. Asthma attacks can occur suddenly and can be severe, leading to hospitalization or even death. Allergies, on the other hand, usually only cause mild to moderate symptoms and are not usually life-threatening.

Another important difference is that while allergies are caused by an immune system response to an allergen, asthma can be caused by a variety of factors, including allergens, irritants, and exercise. Additionally, asthma is a chronic condition that requires ongoing management, while allergies can often be managed with medications or avoidance of the allergen.

The treatments for asthma and allergies also differ significantly. Asthma is typically treated with a combination of medications, including inhaled corticosteroids, which reduce inflammation in the airways, and bronchodilators, which relax the muscles around the airways to allow air to flow more easily. For severe asthma, biologic medications that target specific inflammatory pathways in the body may also be used.

Allergies can be treated with medications such as antihistamines, which block the effects of histamine, or nasal corticosteroids, which reduce inflammation in the nasal passages. In some cases, allergy shots, or immunotherapy, may be used to desensitize the immune system to the allergen.

The following table highlights the major differences between Asthma and Allergies −





Asthma is an inflammation of the airways causing bronchoconstriction.

An allergy is an unusual and unpleasant response by the immune system to some substance that you are exposed to in the environment.


Symptoms of asthma include wheezing, difficulty breathing, chest tightness, and coughing.

Symptoms of allergies vary according to the type of allergy and can include gastric distress, congested nose, sneezing, runny nose, watery eyes, skin rashes, hives, and swelling.


Asthma is diagnosed with a physical exam, lung function tests, spirometry and with a bronchial challenge test.

An allergy can be diagnosed by using blood tests and skin prick tests.

Organs affected

Asthma only affects the lungs and airways.

Allergies can affect multiple organs and systems.


Asthma can be treated with medications including bronchodilator and corticosteroids.

Allergies can be treated by antihistamine medications and injections of epinephrine (EpiPen) in severe cases.


In conclusion, while asthma and allergies can cause similar symptoms, they are fundamentally different conditions. Asthma is a chronic lung condition caused by inflammation and narrowing of the airways, while allergies are caused by an immune system response to an allergen.

Asthma can be life-threatening and requires ongoing management with medications, while allergies can often be managed with medications or avoidance of the allergen.

Updated on: 21-Aug-2023


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