What is an allergy?
You have an allergy when your body overreacts to things that don’t cause problems for most people. These things are called allergens. Your body’s overreaction to the allergens is what causes symptoms.
What is hay fever?
Hay fever, also known as allergic rhinitis (say: “rine-EYE-tis”), is an allergic reaction to pollen. Symptoms of hay fever are seasonal, meaning you will feel worse when the pollens that affect you are at their highest levels. Hay fever is the most common form of allergy. It affects 1 in 5 people.
What are common allergy symptoms?
Symptoms vary depending on the severity of your allergies. Symptoms can include:
- Itching (mostly eyes, nose, mouth, throat and skin)
- Runny nose
- Stuffy nose
- Pressure in the nose and cheeks
- Ear fullness and popping
- Sore throat
- Watery, red or swollen eyes
- Dark circles under your eyes
- Trouble smelling
How does hay fever differ from a cold or the flu?
Hay fever lasts longer than a cold or the flu—up to several weeks—and does not cause fever. The nasal discharge from hay fever is thin, watery and clear, while nasal discharge from a cold or the flu tends to be thicker. Itching (mostly eyes, nose, mouth, throat and skin) is common with hay fever but not with a cold or the flu. Sneezing is more prominent with hay fever and can occur in rather violent bouts.
When should I see a doctor?
If your symptoms interfere with your life, consider seeing your family doctor. Your doctor will probably do a physical exam and ask you questions about your symptoms. Keeping a record of your symptoms over a period of time can help your doctor determine what triggers your allergies.
Causes & Risk Factors
What causes allergies?
You have an allergy when your body overreacts to things that don’t cause problems for most people. These things are called allergens. If you have allergies, when you are exposed to an allergen, your body releases chemicals. One type of chemical that your body releases is called histamine. Histamine is your body’s defense against the allergen. The release of histamine causes your symptoms.
What are the most common allergens?
Pollen from trees, grass and weeds. Allergies that occur in the spring (late April and May) are often due to tree pollen. Allergies that occur in the summer (late May to mid-July) are often due to grass and weed pollen. Allergies that occur in the fall (late August to the first frost) are often due to ragweed. If you are allergic to pollen, you will notice your symptoms are worse on hot, dry days when wind carries the pollen. On rainy days, pollen often is washed to the ground, which means you are less likely to breathe it.
Mold. Mold is common where water tends to collect, such as shower curtains, window moldings and damp basements. It can also be found in rotting logs, hay, mulches, commercial peat moss, compost piles and leaf litter. This allergy is usually worse during humid and rainy weather.
Animal dander. Proteins found in the skin, saliva, and urine of furry pets such as cats and dogs are allergens. You can be exposed to dander when handling an animal or from house dust that contains dander.
Dust. Many allergens, including dust mites, are in dust. Dust mites are tiny living creatures found in bedding, mattresses, carpeting and upholstered furniture. They live on dead skin cells and other things found in house dust.
Diagnosis & Tests
How do I know what I’m allergic to?
Your doctor will do a physical exam and will ask you about your symptoms and when they occur. Your doctor may also want to do an allergy skin test to help determine exactly what is causing your allergy. An allergy skin test puts tiny amounts of allergens onto your skin to see which ones you react to. Once you know which allergens you are allergic to, you and your doctor can decide the best treatment. Your doctor may also decide to do a blood test, such as the radioallergosorbent test (called RAST).
How are allergies treated?
Several medicines can be used to treat allergies. Your doctor will help you determine what medicine is best for you depending on your symptoms, age and overall health. These medicines are more useful if you use them before you’re exposed to allergens.
Antihistamines help reduce the sneezing, runny nose and itchiness of allergies. They’re more useful if you use them before you’re exposed to allergens. Some antihistamines come in pill form (some brand names: Zyrtec, Claritin) and some are nasal sprays (brand names: Astelin and Patanase). Some antihistamines can cause drowsiness and dry mouth. Others are less likely to cause these side effects, but some of these require a prescription. Ask your doctor which kind is best for you.
Decongestants, such as pseudoephedrine and phenylephrine, help temporarily relieve the stuffy nose of allergies. Decongestants are found in many medicines and come as pills, nose sprays and nose drops (some brand names: Sudafed, Afrin, Sinex). They are best used only for a short time.
Nose sprays and drops shouldn’t be used for more than 3 days because you can become dependent on them. This causes you to feel even more stopped-up when you try to quit using them.
You can buy decongestants without a doctor’s prescription. However, decongestants can raise your blood pressure, so it’s a good idea to talk to your family doctor before using them, especially if you have high blood pressure.
Cromolyn sodium is a nasal spray (one brand name: NasalCrom) that helps prevent the body’s reaction to allergens. Cromolyn sodium is more helpful if you use it before you’re exposed to allergens. This medicine may take 2 to 4 weeks to start working. It is available without a prescription.
Nasal steroid sprays reduce the reaction of the nasal tissues to inhaled allergens. This helps relieve the swelling in your nose so that you feel less stopped-up. They are the most effective at treating patients who have chronic symptoms. Nasal steroid sprays are available with a prescription from your doctor. You won’t notice their benefits for up to 2 weeks after starting them.
Eye drops. If your other medicines are not helping enough with your itchy, watery eyes, your doctor may prescribe eye drops for you.
Allergy shots or sublingual tablets (also called immunotherapy) are an option for people who try other treatments but still have allergy symptoms. These shots or dissolvable tablets contain a very small amount of the allergen you are allergic to. They’re given on a regular schedule so that your body gets used to the allergens and no longer overreacts to them. This helps decrease your body’s sensitivity to the allergen. Over time, your allergy symptoms will become less severe.
Allergy shots or sublingual tablets are only used when the allergens you’re sensitive to can be identified and when you can’t avoid them. It takes a few months to years to finish treatment, and you may need to have treatments throughout your life.
How can I avoid allergens?
Pollens. Shower or bathe before bedtime to wash off pollen and other allergens in your hair and on your skin. Avoid going outside, especially on dry, windy days. Keep windows and doors shut, and use an air conditioner at home and in your car.
Mold. You can reduce the amount of mold in your home by removing houseplants and by frequently cleaning shower curtains, bathroom windows, damp walls, areas with dry rot and indoor trash cans. Use a mix of water and chlorine bleach to kill mold. Open doors and windows and use fans to increase air movement and help prevent mold.
Don’t carpet bathrooms or other damp rooms and use mold-proof paint instead of wallpaper. Reducing the humidity in your home to 50% or less can also help. You can control your home air quality by using a dehumidifier, keeping the temperature set at 70 degrees, and cleaning or replacing small-particle filters in your central air system.
Pet dander. If your allergies are severe, you may need to give your pets away or at least keep them outside. Cat or dog dander often collects in house dust and takes 4 weeks or more to die down.
However, there are ways to reduce the amounts of pet dander in your home. Using allergen-resistant bedding, bathing your pet frequently, and using an air filter can help reduce pet dander. Ask your veterinarian for other ways to reduce pet dander in your home.
Dust and dust mites. To reduce dust mites in your home, remove drapes, feather pillows, upholstered furniture, non-washable comforters and soft toys. Replace carpets with linoleum or wood. Polished floors are best. Mop the floor often with a damp mop and wipe surfaces with a damp cloth. Vacuum regularly with a machine that has a high-efficiency particulate air (HEPA) filter. Vacuum soft furniture and curtains as well as floors. Install an air cleaner with a high-efficiency particulate or electrostatic filter. Wash carpets and upholstery with special cleaners, such as benzyl benzoate or tannic acid spray. Wash all bedding in hot water (hotter than 130°F) every 7 to 10 days. Don’t use mattress pads. Cover mattress and pillows with plastic covers. Lower the humidity in your home using a dehumidifier.
Things that can make your allergy symptoms worse
- Aerosol sprays
- Air pollution
- Cold temperatures
- Irritating fumes
- Tobacco smoke
- Wood smoke
Questions to Ask Your Doctor
- Could anything else, such as a cold or the flu, be causing my symptoms?
- How do I figure out what I’m allergic to?
- Is my allergy seasonal?
- I am allergic to _____. Am I at risk for any other allergies?
- What changes can I make at home to help relieve my symptoms?
- Will any over-the counter medicines help relieve my symptoms?
- What should I do if my symptoms get worse or don’t respond to the treatment you’ve prescribed?
- Do I need to see an allergy specialist (called an allergist or immunologist)?