Allergy: A Complete Guide To Understanding Allergies
Allergy is a medical condition in which our body’s immune system reacts to an allergen, i.e., a substance that enters the body from outside. This substance may be pollen, fragrance particles, foods, etc. Allergens can be introduced through breathing or contact with surfaces as well.
When we are allergic to something, our immune system produces antibodies to fight those substances which may be otherwise harmless, but our body treats them as harmful foreign agents.
The intensity of allergic reactions varies from person to person, ranging from minor irritation or inflammation to anaphylaxis—a fatal medical emergency. Although most allergies are incurable and require caution and care, certain treatments can help eliminate unwanted bodily reactions.
Types and symptoms
There are various types of allergies, some of which are seasonal while others are year-round. Some of these may persist for a lifetime as well. Since allergies are caused by different kinds of allergens, they can be categorised based on their cause as follows:
- Food Allergy: It occurs when our immune system identifies certain foods as harmful, and it then reacts to this food by developing allergic symptoms. Food allergies can be further divided into two subcategories based on the involvement of immunoglobulin E (IgE).
- IgE mediated: This condition occurs when immunoglobulin E antibodies react to certain foods. The common foods that cause this kind of allergy are eggs, peanuts, soy, wheat, fish, or any other sea creatures used as food, milk, etc.
- Non-IgE mediated: Some parts of the body may react to certain foods and cause allergic reactions. However, IgE is not involved in such reactions.
Food allergy may cause:
- Hives (itchy, red, and raised rashes)
- Angioedema (swelling of the mouth, face, throat, etc.)
- Itching in the mouth
- Difficulty in swallowing
- Nausea or vomiting
- Diarrhoea or stomach pain
- Shortness of breath
- Dizziness or light-headedness
Drug/Medicine Allergy: There may be times when we develop immune responses to certain drugs/medicines causing this type of allergy.
Symptoms: When we develop this kind of allergy, we may exhibit the following signs:
- Hives and/or rashes
- Runny nose
- Wheezing or shortness of breath
Insect Allergy: Many people develop allergies when they interact with stinging insects like bees, wasps, hornets, etc., or biting insects such as mosquitoes, bedbugs, and fleas.
Symptoms: The following may be signs of insect allergy:
- Swelling of lips, tongue, or throat
- Shortness of breath/wheezing (a whistling sound while breathing)
- Dizziness or fainting
- Skin rashes
- Vomiting, bloating, stomach pain, or diarrhea
Latex Allergy: Latex is a protein that exists in the sap of a Brazilian tree called Hevea brasiliensis. It is commonly referred to as natural rubber. Coming in contact with natural rubber products like balloons, rubber gloves, balls, condoms, diaphragms, etc. can result in allergic reactions in some people.
Symptoms of latex allergy: Latex allergy invokes:
- Runny nose
- Scratchy throat
- Breathing difficulty
- Itchy & watery eyes
Pollen Allergy: It is one of the most common seasonal allergies. Pollen is tiny grains found in flowers, plants, or trees. This pollen, being light, can travel through air or insects.
Many people experience sneezing, an itchy nose, a runny or stuffy nose, and red and watery eyes when they are allergic to pollen grains. This kind of allergy is also called ‘hay fever.’
Experts call it ‘seasonal allergic rhinitis’.
Symptoms of pollen allergy: Allergy because of pollen may exhibit the following signs:
- Nasal congestion
- Blocked sinuses
- Itchy roof of mouth or throat
Pet Allergy: Pets with fur have dander, urine, saliva, dust, pollen, etc. on their fur which in turn makes certain people allergic to them. Pet allergens can transfer to the membranes that line the nose and eyes and may cause itching, swelling, and even inflammation in those parts of the body.
Symptoms: Pet allergy may cause:
- Runny nose
- Facial pressure & pain
- Itchy or watery eyes
- Nasal Congestion
Anaphylaxis: Some allergies to food and insects can cause the body to react severely. Such a medical condition is called anaphylaxis.
It is a life-threatening allergic reaction and occurs rapidly within seconds or minutes of exposure to a substance that one is allergic to.
Symptoms: One may experience the following in this condition:
- Skin rashes
- Nausea & vomiting
- Loss of consciousness
- Severe problem in breathing
- Drop in blood pressure
These are a few common types of allergies. The list goes on as people can develop allergies to anything that does not belong to their body.
Allergies are influenced by environmental factors and elements in the air such as insects, pollens, micro-particles, floral fragrances, mist, etc. Some other factors responsible for allergies include heredity, age, race, and sex of a person.
It is important to mention that allergic reactions are easily inherited from parents. Along with these, passive smoking and pollution can also act as allergens.
Stages & grades of allergy
Allergies have a vast area of function based on their causes. Allergies can be a sign of a serious or long-term disease/disorder and can indicate certain stages of such disease.
British immunologists Coombs and Gell classified the allergies into Type I, II, III, and IV. The first three types of allergic reactions occur within 24 hours of exposure, so they are called immediate reactions.
Type IV reactions take longer than 24 hours to show up.
Type I or anaphylactic reactions (protein mediated): These allergic reactions occur immediately after coming into contact with the allergens. Histamine and other chemicals are released in the body in response to the reactions and inflammation and swelling are caused thereafter. E.g., Anaphylaxis, allergic rhinitis, bronchial asthma, allergic dermatitis.
Type II (cytotoxic reactions): These reactions are mediated by proteins IgG and IgM which damage cells. Such allergic reactions may be observed in autoimmune neutropenia, autoimmune hemolytic anaemia, and immune thrombocytopenia.
Type III (immune complex reactions): In this type of allergic reaction, IgG and IgM antibodies react with allergen and form immune complexes which are responsible for the reaction. These reactions can be seen in lupus, serum sickness, and Arthus reaction.
Type IV (cell-mediated reactions): These allergic reactions take around 48-72 hours or longer to show any symptoms. Such cell-mediated reactions may indicate the existence of tuberculosis and fungal infections.
Diagnostic procedures of allergy
The tests commonly used by doctors to diagnose allergies include the following:
- Intradermal Skin Test: A small amount of allergen is injected into the outer layer of the skin and any reaction on the skin is then observed for confirmation of the allergen.
- Blood tests for Immunoglobulin E: In case of certain skin conditions or in case of medications that interfere with the skin testing, your doctor may prescribe a blood test. In this test, a small amount of allergen is added to the blood sample and then the number of antibodies produced is measured. This test is referred to as the Specific IgE test.
- Patch test: In this, the doctor will place a tiny amount of allergen on your skin and cover it with a bandage to discover possible reactions from your immune system after around 48 hours.
br>This test is used to determine contact dermatitis.
- Skin Prick Test (SPT): A small drop of a possible allergen is placed on the skin and then the skin is scratched with the help of a needle to confirm an allergy.
- Physician-supervised Challenge tests: In this kind of examination, your doctor will ask you to eat or inhale a tiny amount of allergen. The doctor performs this test with possible medication. This test may be supervised because of the risk of anaphylaxis.
Your doctor at Yashoda Hospital and Research Centre, Nehru Nagar, Ghaziabad may prescribe the following to treat your condition:
Medications: Some over-the-counter or prescription medicines in the form of pills, liquid, sprays, eye drops, etc. may be prescribed based on your condition.
Allergen avoidance: Your doctor will assist you in identifying the possible allergens and suggest ways to avoid them to prevent allergic reactions.
Immunotherapy: In case of severe allergies or when the allergies are not treated completely by the prescribed treatment, your doctor may recommend immunotherapy.
It is a series of injections made from purified allergen extracts given for years to treat your allergic condition.
Emergency epinephrine: Epinephrine or adrenaline is a hormone produced in your body by the adrenal glands. If you have severe allergies to certain foods, insects, etc., an epinephrine shot or epinephrine-auto-injector may be prescribed to you to get out of an emergency condition. Epinephrine shots may come under the names such as EpiPen, Auvi-Q, etc.
Make sure that you seek treatment from the best doctors at Yashoda Hospital and Research Centre, Nehru Nagar, Ghaziabad, if you notice symptoms and signs of an allergic reaction:
Dr Mudit Mohan has a rich professional experience of 22 years in this field. His expertise lies in the treatment of infectious diseases and autoimmune diseases, cardiology, diabetes, and thyroid disorders. He has been a part of various UNICEF programs and has also delivered many important lectures on internal medicine.
Dr. Saurabh Gupta is a highly experienced and dedicated doctor in the field of medicine with more than 16 years of experience in internal medicine. His specialisations include expertise in treating diseases of the chest and allergies.
Dr. Neerav Tya is a pulmonologist (lung and chest specialist) with experience of more than 29 years. He possesses expertise in tuberculosis, asthma, bronchiectasis, and pneumonia, among others.
Dr. Brijesh Prajapat is a senior consultant—in pulmonary and critical care—at Yashoda Hospital and Research Centre. He possesses expertise in pulmonary medicine, sleep medicine, critical care medicine, COPD, treatment of various kinds of allergies, etc.
Dr. Rajeev Jain is one of the most experienced specialists at Yashoda Hospital and Research Centre, Nehru Nagar, Ghaziabad. He is a dynamic venereologist and dermatologist and holds an experience of over 18 years in treating skin conditions and diseases like psoriasis, eczema, dermatitis, etc.
Dr. Anup Kumar Tiwary is one of the most accomplished dermatologists at Yashoda Hospital and Research Centre, Nehru Nagar, Ghaziabad. He is an MBBS and MD (dermatology) and holds a fellowship in dermatology, hair transplant, and Laser MIADVL.