Allergies 101

Key Takeaways

For some, sneezing, a runny nose, and itchy eyes are a natural response when trees flower and plants bloom. And some people, who might experience food allergies or be sensitive to indoor irritants like dust and pet dander, are eager to banish their allergy symptoms year-round. 

Here’s a quick look at what allergies are, and your best options to eliminate their symptoms.

What are allergies?

Allergies are caused by the immune system overreacting to harmless substances in the world around us. Common allergens include pet dander, dust mites, food (like peanuts or shellfish), and pollen. When an allergic person is exposed to an allergen, the body produces a protein to fight it off, along with the chemical histamine and some other inflammatory chemicals. That protein and histamine can irritate the nasal passages, eyes, and throat, producing allergy symptoms.

Allergic rhinitis, or hay fever, is a common reaction to inhaled allergens. Seasonal allergy symptoms can affect you only in certain seasons, or they can be triggered year-round. Pollen counts or ragweed might be allergy triggers in warm weather (what most of us consider allergy season), but dusty indoor air is just as irritating to some people in the winter. 

What are seasonal allergies?

Seasonal allergies were nicknamed “hay fever” because they would bedevil farmers during the spring and summer hay-cutting season. Today, it’s a catch-all term for symptoms caused by a variety of outdoor allergens, including tree pollens, grass pollens, and weed pollens. The more medical term is “allergic rhinitis.”

What causes an allergic reaction? In the case of pollen, it’s a collection of fine particles that are released by plants during their reproductive cycles. Those particles contain proteins that irritate the eyes, nose, sinuses, and throat once they’re inhaled. The body launches an immune response to get rid of the irritants, creating antibodies and releasing a chemical called histamine, which causes typical allergy symptoms like sneezing and itching. 

Seasonal allergies can occur in certain seasons (like spring and/or fall), or they can be triggered year-round (perennial). And they’re extremely common: According to the World Allergy Organization (WAO), currently, approximately 10 to 30% of adults and 40% of children are affected.

The symptoms of seasonal allergies may be similar to a cold at first, including:

- Sneezing or a runny nose

- Postnasal drip

- Nasal, ear or sinus congestion

- Watery or itchy eyes

- Itchy throat

- Less common symptoms include wheezing, shortness of breath, and headache.

Is it a cold, or could it be allergies?

Allergies and a common cold can have similar symptoms and share a common denominator: They can leave you feeling pretty miserable. But it’s important to know the difference between a cold and allergies so you can treat the symptoms most effectively and find relief as soon as possible.

The common cold is caused by a virus. According to the US National Institute of Health, more than 200 different viruses are known to cause cold symptoms. Common symptoms of a cold include a cough, sneezing, a runny or stuffy nose, and fatigue. You might also have a sore throat, headache, fever, and body aches. If you do, it’s pretty likely you have a cold—a sore throat and headache are rarely symptoms of allergies, and fever and body aches never are. There’s a reason the cold is called common: The average adult gets two to three colds annually.

Your doctor or pharmacist may recommend over the counter remedies for the common cold. Decongestants, cough syrups, and saline nasal rinses may help with nasal congestion and coughing. Over-the-counter pain relievers such as ibuprofen or acetaminophen can lower fever and reduce body aches. Using an ultrasonic humidifier in your bedroom can moisten the air, which can help soothe a sore throat, nasal dryness, and coughing.

Allergies are not caused by a virus. They happen when the immune system overreacts to typically harmless substances in the world around us. Allergy symptoms can include sneezing, a cough, a runny or stuffy nose, a rash, and itchy eyes or watery eyes. 

If you have itchy or watery eyes or a rash, chances are you’re experiencing allergies: Those symptoms aren’t associated with the common cold. 

The most important criteria for telling whether you have a cold vs. allergies are those exclusive symptoms: Again, allergies rarely cause a sore throat, headache, fever, and body aches, while the common cold rarely comes along with a rash or itchy or watery eyes.

But absent those symptoms, you can consider the time of year and your own allergy history. Tree pollens peak in the spring, while ragweed pollen makes a lot of people miserable starting around mid-August. But allergies can happen year-round: People who are sensitive to mold can see an uptick in allergy symptoms in the summer, while indoor allergens such as dust mites and pet dander are always around. You can also consider the duration of symptoms: Cold symptoms usually last seven to ten days, while allergy symptoms can last for weeks.

How to treat allergies

For most people, allergy symptoms can be managed and controlled, but allergies can’t be cured.


The easiest way to prevent allergies is to avoid the allergens that bother you. This can be easier said than done. If you’re allergic to cats, you can choose to get a different pet, and if you’re sensitive to shellfish, you can skip over that part of the menu. But some allergens, like pollen and dust, are all around us and can be more difficult to avoid.

Allergy medications

Over-the-counter antihistamines, corticosteroids, decongestants, nasal sprays, or eye drops can help ease allergy symptoms. If your symptoms endure or are severe, a doctor may direct the use of prescription medications that can reduce inflammation in your nose and sinuses, or refer you to an allergist for further testing and treatment.

Allergy shots

If your allergy symptoms are chronic and bothersome, your healthcare provider might recommend allergy shots. This is a form of immunotherapy that helps your immune system acclimate to certain allergens. Allergy shots involve receiving regular injections of tiny amounts of an allergen or combination of allergens, and they can take months or years to work.

Natural remedies

Some home remedies may bring relief from allergy symptoms, such as using a saline rinse (most commonly, in a device called a neti pot) to ease nasal congestion.

Air purifiers (HEPA filters)

Using an air purifier and/or vacuum with HEPA filters can help cut down on indoor allergens, which can cause sneezing, a runny nose, coughing, and itching. HEPA (high-efficiency particulate air) filters remove 99.97% of dust, pollen, mold, bacteria, and other airborne particles with a size of 0.3 microns. A HEPA air purifier may remove those irritants from the air, while a vacuum with a HEPA filter may trap dust and allergens, preventing them from being expelled in the exhaust.

Hypoallergenic cleaning supplies and fabrics

A wide variety of hypoallergenic products are available, which eliminate allergens on surfaces and won’t irritate you while you’re cleaning. These include anti-allergen sprays, unscented cleaners and detergents, and dust-trapping cloths (such as microfiber). If you’re sensitive to fragrance, look for products marked “hypo-allergenic,” unscented, or “free and clear.”

Allergen-reducing cleaning techniques

Aside from using a vacuum with a HEPA filter regularly, there are other cleaning techniques you can use to reduce bothersome allergens around the house. 

They include:

  • Washing bed linens often: bed sheets attract dust mites, which are a major source of indoor allergies. Experts recommend washing sheets in hot water once a week. 
  • Dusting and wiping down surfaces regularly 
  • Reducing the number of soft surfaces in your home (such as carpets, curtains and throw blankets), which can harbour dust
  • Wearing a dust mask when cleaning
  • Dusting with a spray, damp cloth, or static duster, to reduce the amount of airborne dust
  • Eliminating possible sources of mold in your home, such as damp spots or leaking fixtures
  • Hiring an exterminator to eliminate any sign of cockroaches and mice

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