Many people around the world suffer from allergies. It is estimated that allergic rhinitis, a form of allergy, affects 10-30% of the population globally. Allergies are a leading cause of chronic illness and impose a significant financial burden on the healthcare system.
Allergies can cause many distressing symptoms like itchiness, nasal congestion, runny nose, and watering eyes. But for some allergies can cause other serious symptoms like shortness of breath.
Here we will take an in-depth look at allergies, and the causes and mechanisms behind them. We will also take you through allergic rhinitis and allergic asthma: the signs and symptoms, diagnosis, and how we can prevent them.
Allergies: What are they and what causes them?
Allergies occur when your immune system reacts to any foreign substance. It could be something you eat, inhale into your lungs, touch or inject into your body. While these substances are generally inert and are harmless, it is the body’s exaggerated response, or hypersensitivity, that initiates allergy.
Causes of allergies
Your allergies can be caused by many different substances, known as allergens, such as :
- Pollen (from tree, grass, weed, flowers)
- House dust mites
- Animal dander
- Insect venom
- Rodent urine
- Food (nuts, wheat, soy, milk, fish, eggs, sulfite, casein)
- Plant allergies (poison oak, poison ivy, poison sumac)
- Contact allergens (fragrance, metals like nickel)
- Sun or ultraviolet (UV) radiation
Mechanism of allergy
The underlying mechanism of allergy involves immunoglobulin E (also known as IgE antibody).
These antibodies are made when the body first encounters the allergens, which then attach to specialized cells called mast cells and basophils. This process is known as “sensitization”
When the body comes into contact with the same allergen again, the mast cells release an inflammatory chemical known as histamine. These chemicals then start the allergic reaction in the body which leads to sneezing, rashes, and watery eyes.
Can allergies cause shortness of breath?
Breathing problems such as shortness of breath are more commonly associated with respiratory diseases like asthma but can also be caused by allergies.
The typical symptoms of allergies however are:
- Sneezing, coughing, and runny nose
- Watery eyes
- Skin rash
- Stomach and bowel problems
- Swollen lips and mucous membrane
The mechanism behind the shortness of breath caused by allergy
Allergies can affect how you breathe by two mechanisms.
Also known as hay fever, allergic rhinitis affects your nose and sinuses. It can lead to nasal congestion, itchiness of the nose and the eye, and sneezing. If your nose is heavily congested, it can lead to difficulty breathing through the nose.
When your allergies have you gasping for breath, it’s known as allergy-induced asthma or allergic asthma. You will have difficulty breathing after you inhale an allergen. This occurs because your airways tighten and your lungs become inflamed.
The IgE produced by the body during an allergic response causes the release of additional inflammatory mediators like prostaglandins and leukotrienes. Together, these mediators cause contraction of the muscles of the airways. It also leads to swelling and the production of mucous. This results in narrow and constricted airways making it difficult for you to breathe.
Signs that you may have allergic rhinitis and allergic asthma
If you have allergic asthma, you are likely to develop symptoms of both allergies as well as asthma.
Allergic asthma can develop in people who have been diagnosed with asthma. Apart from shortness of breath, it can cause cough, wheezing, tightness of the chest, and rapid breathing .
While the triggers for allergic asthma are usually in the environment rather than food, the duration of symptoms depends upon the allergens. For eg., if pets or dust mite on your bedding is triggering your symptoms, you will suffer all year round, whereas if it is due to mold or pollen, it will be seasonal.
In children, the symptoms can be more subtle like feeling too tired to play. If your child wants to sit on the sidelines while the other kids are running around, he/she may be having trouble breathing. Make sure you check if your child is coughing or wheezing.
How are allergies diagnosed?
If you think you may have allergic asthma, seek help from your health care provider or allergist, the doctors who specialize in diagnosing and treating allergies. It is important to visit a doctor when your symptoms last longer than a week.
Your doctor will take a detailed history of your allergies. He or she will then perform a thorough physical examination. Your doctor may also perform the following tests to detect your allergies:
There are two types of skin tests, the prick and patch tests.
The skin prick test, also known as a puncture or scratch or test, is a procedure that involves placing tiny bits of suspected allergens on the skin of your forearm. The doctor then pricks the skin through the allergen, allowing it to enter the body.
If you are allergic to any substance, within 15 minutes, red tiny raised bumps appear on the skin at the site.
A skin patch test is the gold standard test for delayed allergic reactions. A patch test, unlike a skin prick test, does not involve pricking the skin with needles. Instead, allergens are applied to patches which are then placed on your skin.
These patches are worn for 48 hours, during which you should not bathe. Patches are removed thereafter and irritated skin indicates an allergy.
In a provocation test, you will be exposed to various allergens. The doctor will then see if your body reacts to it.
If you might have allergic rhinitis, liquid extracts of the suspected allergens are placed inside your nose, using a nasal spray or drops. If you sneeze, your nose starts running or if the lining of your nose becomes swollen, you are likely to have allergic rhinitis.
An allergic blood test measures IgE antibodies to specific allergens. The most commonly performed blood test is RAST (radioallergosorbent test). Healthcare providers will draw blood from your arm. The results can take anywhere between a few days to a week.
Lung function test
A lung function test can determine if your asthma is due to allergies. These tests check whether there is an improvement in your breathing after you are given medications to widen the airway (known as bronchodilators). If your airways significantly widen, you are more likely to have asthma.
Spirometry is a lung function test to confirm asthma. It measures how much air you can breathe in and the rate of the airflow. A FeNO test measures the amount of inflammation in your lungs. A peak flow meter will measure the rate at which you can forcefully exhale.
Is allergic asthma dangerous?
One of the most dangerous complications of allergic asthma is anaphylaxis in which many organs of the body, including the heart and lungs, shut down. It is life-threatening if not treated on time.
How do I prevent it?
General measures for preventing allergy and allergy-induced asthma are:
- Avoid triggers that you are aware of. For instance, if you know you are allergic to pollen, stay indoors with the doors and windows shut (especially during the spring season when pollen is high).
If you are allergic to dust, regularly clean, dust, and vacuum your house. Wash beddings and linen more frequently and use an air purifier at home.
- Wear a medical bracelet: Sometimes you may have a serious allergic reaction and you may not be able to communicate. Wearing a medical bracelet (or a necklace) will let others know of your condition and will prompt medical help.
- Keep a diary: If you don’t know what triggers your allergy and how you can avoid them, keeping a diary will help. Track what you eat or activities that you do that cause or worsen your allergic reaction. This will not only help you prevent allergies but also help your doctor identify your triggers.
Even after everything, for some people, allergies are inherited and cannot be prevented. You are more likely to develop allergic asthma if:
- You are a child
- You have a family history of allergies or asthma (including hives, eczema, hay fever,)
- You have asthma or other allergic condition
The frequency of allergies is on the rise, affecting both adults and children. Allergies can cause symptoms ranging from rashes and itching to shortness of breath. Allergy-induced difficulty in breathing can be due to the swelling of the lining of your nose or narrowing and swelling of your airways. Diagnosing the triggers of your symptoms and treating shortness of breath is crucial, as it may potentially have serious complications. If your symptoms persist or worsen with time, always seek help from your healthcare provider.