Allergy is a hypersensitivity disorder in which the body’s immune system reacts to normally harmless substances in the environment. These substances which trigger an allergic reaction in the body are called allergens. Allergy can be caused by anything such as egg, wheat, peanuts, milk, drugs, house dust mites, unhygienic places, cold, rain and even dust. Food allergies are reactions towards certain food components. The most common allergens in foods are proteins. When the allergic reaction is due to a drug, it is said to be a drug allergy. They are most commonly seen with antibiotics followed by anti-tumour drugs.
Allergens cause an immune system response in the person’s body leading to symptoms such as sneezing, skin rash, hives, and itching of the skin or eyes, swelling of face or tongue, running nose, hoarseness of voice, cough, etc. Allergies can play a major role in conditions such as asthma. Drug allergy may cause swelling or tightening of the airways, dizziness or light headedness, rapid pulse, or even loss of consciousness. An anaphylactic attack or anaphylaxis is a severe type of allergic reaction which can often be sudden and cause severe symptoms like choking, organ failure and even death.
Depending on the type of allergy diagnostic tests may include skin tests, blood tests, oral challenge test, drug provocation test, etc. Self-medication for allergy should be avoided. Allergy can be of many types and each one of them need separate medication to be cured. Special diets are the most commonly used treatment for food allergies. But, certain medications and supplements are also used to deal with food allergy symptoms. Adverse reaction to any drug must be notified to the doctor immediately. Epinephrine (adrenaline) injection is used to handle medical emergencies due to complications. An anaphylactic attack is a medical emergency.
A person could be allergic to one or several allergens. There are different forms of allergies depending on the type of allergen triggering the response. Here are the most common forms of allergies that people suffer from.
1. Food allergy: Your immune system could trigger a response to proteins present in specific foods you consume. Allergies to nuts, egg, wheat, milk and chickpeas are more common, contributing to 90% of food allergies found in India.
2. Dust allergy: Dust particles can enter your nasal passage and cause blocked nose, cough, sneezing and irritation in the throat.
3. Seasonal allergy: Many people complain about allergic symptoms with a change in climate and season.
4. Pet allergy: You could develop an allergic reaction to skin flakes, dander or saliva of your pet. Moreover, the fur of animals attracts dust and pollen that can worsen allergy symptoms.
5. Drug allergy: Your system could evoke an immune response to either the drug or the chemical generated inside the body by the drug. This type of allergy could be severe and may be fatal
6. Cosmetic allergy: Chemicals used in cosmetics can trigger an immune response causing allergic skin reaction and swelling.
Symptoms of allergies are triggered depending on the part of the system the allergen targets.
Dust, seasonal and pet allergy can cause congestion, runny nose, swollen eyes, watery eyes, throat irritation and blocked nose.
Food allergy can cause mouth and throat irritation, swelling of the mouth, indigestion, vomiting, nausea, stomach cramps, bloating and diarrhea. Some food allergens can also trigger respiratory symptoms like wheezing, runny nose, sneezing and coughing.
Drug allergy can cause itchy skin, redness, swelling, wheezing and skin rash
Cosmetic allergy can cause redness, swelling and flaking of skin. It can cause itching and skin rashes.
Certain allergies can become severe. If you develop any of the following symptoms, you should see a doctor immediately.
Difficulty in breathing or extreme shortness of breath
Tightness in the chest, congestion or chest pain
If eczema progresses to thickening and swelling of skin
Hives or itchy swelling on the skin
Anaphylaxis or a life-threatening allergic reaction
To determine whether you’re suffering from an allergic reaction, your doctor may recommend a simple blood test. ‘The general test for the diagnosis of allergies include a CBC (Complete Blood Count). If your results show an increased eosinophil level and IgE level, then you might be diagnosed with an allergy,’ says Dr Abha Shroff, chief pathologist and director at Disha Pathology Labs, Mumbai. To determine the allergen causing the undesirable reaction, you may have to undergo the following tests:
Scratch skin test: A small drop of the suspected allergen is placed on the surface of the skin. Using a needle, the surface is scratched or priked lightly so as to allow the allergen to get absorbed. Any immediate redness, swelling or change in the surface of skin may indicate allergy towards the allergen under test.
Immunoassays: In certain situations, such as extensive eczema, skin tests cannot be performed as it may lead to dangerous consequences. In such cases, the doctor may recommend blood tests such as the RAST (Radioallergosorbent assay) and the ELISA (Enzyme-linked immunosorbent assay). Both the tests detect the presence of IgE antibodies in the blood of patients. They are expensive and the results are not readily available. ‘The newest advanced tests for allergy testing are blood tests that do not require fasting. The skin prick tests has been replaced by blood testing, ‘says Dr Shroff.
Allergies cannot be cured. The best way to prevent them is to avoid the allergen. But for that you need to undergo proper tests to identify the causative allergen.
Medicines given for allergies help reduce the symptoms and the effect of substances released during an allergic reaction on the surrounding tissues. There are different groups of medications given for allergic reactions depending on the allergen triggering the reaction.
Antihistamines: These are the most common class of drugs that relieve the symptoms of allergies. They work by blocking the action of substances or molecules called histamines that are released by your system when it detects an allergen.
Decongestants: Decongestants are another class of medicines that may be given to relieve symptoms like nasal congestion often caused by dust allergy or pet allergy.
Corticosteroids: They specifically act on the linings of the nasal passage and airways to clear congestion and reduce respiratory symptoms. Here’s more information on side-effects, interaction and overdose of allergy medicines.