Allergies are a common part of life for millions of people around the world. Whether it’s a sneeze-filled spring day or a reaction to certain foods, allergies can range from mildly annoying to life-threatening. Understanding what causes allergies, how they affect your body, and how to manage them can help you live more comfortably. In this guide, we’ll break down the basics of allergies, helping you better understand the key information you need to know.

What is an allergy, exactly?

An allergy occurs when your immune system reacts to something that it mistakenly sees as harmful, even though it’s usually harmless to most people. These substances, called allergens, include things like pollen, certain foods, or pet dander. When your body encounters an allergen, it releases chemicals like histamine, which cause allergy symptoms such as sneezing, itching, and swelling.

Common types of allergies

There are many types of allergies, and they affect people in different ways. Here are some of the most common ones:

• Food allergies: Some people react to foods like peanuts, shellfish, eggs, or milk. Reactions can range from mild symptoms like hives to more severe reactions such as difficulty breathing. Don’t confuse these with food intolerances, which generally trigger digestive discomfort rather than an immune response.
• Seasonal allergies (hay fever): Allergens like pollen from trees, grass, or flowers, can trigger sneezing, runny nose, and itchy eyes.
• Skin allergies: Contact with substances like latex, certain metals, or plants can cause skin reactions, such as rashes or itching.
• Insect sting allergies: Bee stings or insect bites can cause reactions that range from mild swelling to more serious responses.
• Drug allergies: Some medications, such as antibiotics, can cause reactions in certain individuals, leading to symptoms like skin rashes or more severe responses.
• Indoor allergies: Common allergens like dust mites, mould, and pet dander can trigger allergic reactions, particularly in indoor spaces.

Symptoms of allergies

Allergy symptoms depend on the type of allergen and how your body reacts to it. Here are some of the most common symptoms:

• Sneezing and a runny or blocked nose
• Itchy or watery eyes
• Swelling, especially around the face, lips, or throat
• Skin rashes, hives, or itching
• Coughing or wheezing
• Nausea, vomiting, or diarrhoea (especially with food allergies)
• Difficulty breathing in severe cases

Sometimes, people may experience anaphylaxis, which is a serious and potentially life-threatening reaction. Symptoms of anaphylaxis include difficulty breathing, swelling of the throat or tongue, and a sudden drop in blood pressure. If you or someone you know shows signs of anaphylaxis, it’s important to seek immediate medical help and use an epinephrine auto-injector (like an Epipen) if available.

Causes of allergies

The exact reasons people develop allergies aren’t fully understood, but several factors likely play a role. These include genetics, environmental exposures, and how your immune system responds. If you have a family history of allergies, you may be more likely to develop them yourself.

Common allergens include:

• Pollen from trees, grass, and flowers
• Food allergens like peanuts, shellfish, and dairy
• Pet dander from cats and dogs
• Insect stings, particularly from bees and wasps
• Medications such as penicillin and aspirin
• Mould spores, dust mites, and other environmental factors
• Air pollution and environmental changes that may increase exposure to allergens

Experts also suggest that growing up in spotless environments might increase the risk of developing allergies later in life. Known as the hygiene hypothesis, this theory proposes that less exposure to germs and allergens in childhood can make the immune system more likely to overreact to harmless substances later on.

Diagnosing allergies

If you think you have allergies, a healthcare provider can help diagnose the condition through tests and evaluations. Some of the most common tests include:

• Skin prick test: Small amounts of potential allergens are placed on your skin to see if any reactions occur.
• Blood tests: These measure the levels of antibodies (like IgE) in your blood, which are produced in response to allergens.
• Patch tests: These are used for skin allergies by applying allergens to your skin to see if there’s a delayed reaction over a period of time.
• Challenge testing: This is typically used for food or drug allergies and involves gradually introducing the allergen under medical supervision to confirm the diagnosis.

These tests help identify your specific allergens, allowing you to manage and avoid them more effectively.

Managing and treating allergies

The most effective way to manage allergies is to avoid the allergens that trigger a reaction. However, this isn’t always possible, especially with things like pollen or dust that are hard to avoid. Fortunately, there are treatments available that can help you reduce symptoms and improve your quality of life.

Here’s a look at some common treatments:

• Antihistamines: These help block the effects of histamine, the chemical that your body releases during an allergic reaction. Antihistamines are great for managing symptoms like sneezing, itching, and a runny nose. They’re available over the counter or by prescription.
• Decongestants: These help relieve nasal congestion, making it easier to breathe when your allergies are flaring up.
• Corticosteroids: Available as nasal sprays, creams, or pills, these reduce inflammation and can help ease allergy symptoms.
• Immunotherapy: This longer-term treatment introduces small amounts of an allergen to your body over time, which helps reduce your immune system’s sensitivity to it. This can be done through injections or tablets placed under the tongue.
• Biologics: These newer treatments are used for more severe cases, such as asthma or chronic hives. They target specific parts of the immune response to reduce allergy symptoms when other treatments aren’t effective.

If you have severe allergic reactions, particularly anaphylaxis