Understanding Allergies

Allergies are among the most common chronic conditions worldwide, affecting millions of people of all ages. From seasonal sniffles to life-threatening reactions, allergies can range from a minor inconvenience to a serious health concern. Understanding what triggers your allergies and how to manage them can help you breathe easier and live more comfortably.

What Are Allergies?

An allergy occurs when your immune system reacts to a foreign substance (allergen) that doesn’t cause a reaction in most people. When you have an allergy, your immune system mistakenly identifies the allergen as harmful and produces antibodies called Immunoglobulin E (IgE). These antibodies trigger the release of chemicals like histamine, causing allergy symptoms.

Allergies affect approximately 50 million Americans and are the sixth leading cause of chronic illness in the United States. They can develop at any age, though many allergies first appear during childhood. Some people outgrow certain allergies, while others develop new allergies as adults.

Common types of allergies:

• Seasonal allergies (Allergic rhinitis/Hay fever) - Triggered by pollen from trees, grasses, and weeds
• Perennial allergies - Year-round allergies to dust mites, pet dander, mold, or cockroaches
• Food allergies - Reactions to specific foods like peanuts, tree nuts, milk, eggs, wheat, soy, fish, or shellfish
• Drug allergies - Reactions to medications like penicillin or aspirin
• Insect allergies - Reactions to stings from bees, wasps, hornets, or fire ants
• Latex allergies - Reactions to proteins in natural rubber latex
• Skin allergies - Including contact dermatitis and eczema

Causes and Risk Factors

Allergies develop when your immune system identifies a harmless substance as dangerous. The exact reason why some people develop allergies and others don’t isn’t fully understood, but several factors play a role.

Risk factors:

• Family history of allergies or asthma
• Having asthma or other allergic conditions
• Being a child (though new allergies can develop at any age)
• Reduced exposure to infections in early childhood (hygiene hypothesis)
• Born during high pollen season
• Exposure to allergens at a time when immune function is weakened

Common allergens:

Airborne:

• Tree, grass, and weed pollen
• Dust mites
• Mold spores
• Pet dander (proteins from skin, saliva, and urine)
• Cockroach droppings

Food:

• Peanuts and tree nuts
• Milk and dairy products
• Eggs
• Wheat
• Soy
• Fish and shellfish
• Sesame

Other:

• Insect stings (bee, wasp, hornet venom)
• Medications (penicillin, sulfa drugs, NSAIDs)
• Latex
• Metals (nickel)
• Plants (poison ivy, poison oak)

Common Symptoms

Allergy symptoms depend on the type of allergen and how you’re exposed to it.

Respiratory allergies (hay fever):

• Sneezing
• Runny or stuffy nose
• Itchy, watery, or red eyes
• Itchy nose, roof of mouth, or throat
• Postnasal drip
• Cough
• Facial pressure or pain
• Reduced sense of smell or taste
• Fatigue

Food allergy symptoms:

• Tingling or itching in the mouth
• Hives, itching, or eczema
• Swelling of lips, face, tongue, throat, or other body parts
• Abdominal pain, diarrhea, nausea, or vomiting
• Dizziness or lightheadedness
• Anaphylaxis (severe, life-threatening reaction)

Skin allergy symptoms:

• Hives (raised, itchy welts)
• Itching
• Redness
• Flaking or peeling
• Swelling

Insect sting allergy symptoms:

• Large area of swelling at the sting site
• Hives or itching all over the body
• Cough, chest tightness, or wheezing
• Anaphylaxis

Anaphylaxis warning signs (emergency):

• Difficulty breathing or shortness of breath
• Rapid, weak pulse
• Skin rash or flushing
• Nausea and vomiting
• Dizziness or fainting
• Swelling of the throat
• Drop in blood pressure (shock)

Diagnosis

Proper diagnosis helps identify your specific triggers and guides effective treatment.

Diagnostic methods:

• Medical history - Detailed discussion of your symptoms, when they occur, and potential triggers
• Physical examination - Checking for signs of allergic reactions
• Skin prick test - Small amounts of potential allergens are pricked into the skin; a raised bump indicates a reaction
• Blood test (Specific IgE test) - Measures antibodies to specific allergens in your blood
• Patch test - Allergens are applied to patches worn on the skin for 48 hours to test for contact allergies
• Elimination diet - Removing and gradually reintroducing foods to identify food allergies
• Oral food challenge - Consuming gradually increasing amounts of a suspected allergen under medical supervision
• Pulmonary function tests - If allergic asthma is suspected

Treatment Options

Treatment aims to reduce symptoms, prevent reactions, and manage allergies long-term.

Avoidance: The most effective treatment is avoiding known allergens when possible.

Medications:

Antihistamines:

• Block histamine to relieve sneezing, itching, runny nose, and hives
• Available as pills, liquids, nasal sprays, and eye drops
• Newer versions (cetirizine, loratadine, fexofenadine) cause less drowsiness

Decongestants:

• Relieve nasal congestion
• Available as pills, liquids, nasal sprays, and drops
• Don’t use nasal decongestant sprays for more than a few days (rebound congestion)

Corticosteroids:

• Reduce inflammation and swelling
• Available as nasal sprays, inhalers, creams, and pills
• Nasal corticosteroids are highly effective for allergic rhinitis

Leukotriene modifiers:

• Block inflammatory chemicals
• Helpful for allergic asthma and rhinitis

Mast cell stabilizers:

• Prevent release of inflammatory chemicals
• Available as eye drops and nasal sprays

Epinephrine auto-injector (EpiPen):

• Emergency treatment for anaphylaxis
• Must be carried at all times if at risk for severe reactions

Immunotherapy:

• Allergy shots - Gradually increasing doses of allergens over 3-5 years to build tolerance
• Sublingual immunotherapy - Tablets placed under the tongue for certain allergies

What You Can Do

Managing allergies effectively involves both avoiding triggers and treating symptoms when they occur.

1. Identify your triggers - Work with an allergist to determine exactly what you’re allergic to. This allows you to take targeted avoidance measures.

2. Reduce indoor allergens - Use allergen-proof mattress and pillow covers. Wash bedding weekly in hot water. Keep humidity below 50% to discourage dust mites and mold. Use a HEPA filter air purifier.

3. Manage outdoor allergens - Check pollen counts and limit outdoor activities when counts are high. Keep windows closed during pollen season. Shower and change clothes after being outdoors. Don’t hang laundry outside to dry.

4. Control pet allergens - Keep pets out of bedrooms. Bathe pets regularly. Consider HEPA filters. If allergies are severe, you may need to consider pet-free living.

5. Prevent food allergy reactions - Read food labels carefully. Ask about ingredients when eating out. Inform restaurants about your allergies. Carry your epinephrine auto-injector at all times.

6. Take medications proactively - For seasonal allergies, start taking medications before symptoms begin. Consistent use of nasal corticosteroids is more effective than as-needed use.

7. Create an emergency action plan - If you have severe allergies, work with your doctor to create an anaphylaxis action plan. Ensure family, friends, and coworkers know how to help in an emergency.

8. Wear medical identification - If you have severe allergies, wear a medical alert bracelet or necklace identifying your allergies.

9. Clean regularly - Vacuum frequently with a HEPA-filter vacuum. Dust with a damp cloth. Wash stuffed animals and throw rugs regularly.

10. Consider immunotherapy - If allergies significantly impact your quality of life, discuss allergy shots or sublingual tablets with your allergist.

When to See a Doctor

Consult a healthcare provider or allergist if:

• Over-the-counter medications don’t control your symptoms
• Symptoms interfere with your daily life or sleep
• You’re not sure what’s causing your symptoms
• You want allergy testing to identify triggers
• You’re interested in immunotherapy
• You have asthma and allergies together

Seek emergency care if you experience signs of anaphylaxis:

• Difficulty breathing or severe shortness of breath
• Rapid pulse
• Dizziness or fainting
• Swelling of the throat or tongue
• Hives covering large areas of the body
• Severe abdominal pain, nausea, or vomiting after food exposure
• Any symptoms after an insect sting if you have known insect allergy

Use your epinephrine auto-injector immediately if prescribed and call 911.

Key Takeaways

• Allergies occur when the immune system overreacts to normally harmless substances, releasing chemicals that cause symptoms
• Common allergens include pollen, dust mites, pet dander, certain foods, insect stings, and medications
• Treatment includes avoidance, medications (antihistamines, corticosteroids, decongestants), and immunotherapy for long-term management
• People with severe allergies should carry an epinephrine auto-injector and have an emergency action plan in place