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This guide to allergies will inform you about outdoor (seasonal) and indoor (year-round) allergies, how they are treated, the factors called allergens that cause your allergic reactions, and things you can do to reduce exposure to allergens.
We will compare the advantages and disadvantages of commonly used allergy medications: decongestants, antihistamines, and intranasal corticosteroids.
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:: What causes allergies?
Your immune system works to protect you from bacteria, viruses and other foreign substances. When a person without allergies inhales a foreign substance such as pollen, the mucus in their nasal passages simply moves the substance to the throat, where it is swallowed or coughed out.
If you have an allergy to pollen or other substance, it is because your immune system mistakenly identifies the pollen, called an allergen, as an invader that can do harm, and instead of simply letting the pollen be removed by your body, your immune system activates its response to protect your body, causing allergy symptoms or allergic reactions.
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:: What is the immune system’s response to allergens?
An allergen is any substance that you are allergic to, let's say ragweed pollen for example. If your immune system decides an allergen is a threat, it activates your immune response:
First, cells called T-cells are sent to identify the allergen (also called antigen). Then, T-cells instruct another kind of cells called B-cells to start producing a compound called ImmunoglobulinE (IgE) antibodies. These IgE antibodies are specific to this particular allergen (ragweed pollen in this case). The IgE antibodies bind to mast cells and basophils which are in the lining of your nose. These cells are now armed and ready to directly react to the specific allergen (ragweed pollen) the next time they detect it.
From now on, every time you inhale ragweed pollen, it comes in contact with the ragweed pollen IgE antibodies which in turn stimulate the mast cells and basophils to release inflammatory substances such as histamine. Histamine is a chemical which binds to cells causing them to release fluids, swell and become irritated. Normally this process allows your body to get rid of harmful substances such as bacteria. The reaction of your cells to histamine is the cause of allergy symptoms such as runny, itchy nose, sneezing, coughing, and watery, itchy eyes
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:: How can I tell whether I’m having an allergy attack or a cold?
Allergies, colds, and the flu have some of the same symptoms. Here are some general guidelines to help distinguish allergies from colds or the flu.
Allergies:
- No fever.
- No muscle aches.
- Itchy nose, throat and eyes.
- Nasal mucus secretions are clear and watery.
- Symptoms last longer than a cold (longer than 7 to 10 days).
Cold or the flu:
- Fever present.
- Muscle aches.
- Sore throat.
- Nasal mucus secretions are thicker and not clear.
- Symptoms last for 7 to 10 days.
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:: How common are allergies?
It is estimated that 35 to 40 million people in the United States suffer from seasonal (outdoor) or perennial (year-round/indoor) allergies.
Allergies can start at any age but most commonly develop in the teenage to young adult years.
A family history of allergies increases your risk for developing allergies. If both of your parents have allergies, you have a 75% risk of having allergies too. If only one of your parents has allergies, your risk of having them too is 50%.
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:: What are some common allergens or allergy triggers?
Common indoor allergy triggers or allergens include:
- dust mites 
- mold .
- cockroach waste
- animal dander
Outdoor allergy triggers or allergens are pollen from various grasses, trees and weeds.
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:: What are seasonal allergies?
Seasonal allergies are also called outdoor allergies or hay fever. Seasonal allergies come and go with the change of season that causes particular plants to release pollen. You will usually experience seasonal allergies for a few weeks to a few months at about the same time every year.
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:: What are perennial allergies?
Perennial allergies are also called indoor or year-round allergies. Indoor allergies do not come and go with changes in the season. They are triggered by substances that are found indoors throughout the year such as dust mites, mold and animal dander.
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:: What is perennial non-allergic rhinitis (PNAR)?
Perennial non-allergic rhinitis (PNAR) is also called year-round non-allergic nasal symptoms. PNAR involves nasal symptoms such as stuffy, runny nose and postnasal drip which occurs year-round but is not caused by allergies.
PNAR is caused by environmental triggers such as smoke, pollution, strong odors, spicy foods, temperature changes or cold air.
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:: How are allergies treated?
The seemingly easiest way to treat allergies is to avoid the triggers that cause allergies in the first place. Some practices can reduce your exposure to allergens (see the last 5 questions in this FAQ), but unfortunately, total avoidance is next to impossible when the triggers are all around you in the air you breathe. Therefore medications are primarily used to treat allergy symptoms. Immunotherapy is also an option for treating patients with long-term allergies.
There are three classes of medications to treat the symptoms of allergies: Decongestants, Antihistamines, and Intranasal corticosteroids.
Decongestants:
Decongestants are usually over-the-counter and work to relieve nasal congestion (stuffy nose) by constricting blood vessels thereby decreasing swelling and opening nasal passages. Decongestants are available as nasal sprays and drops or oral formulations such as tablets, capsules or oral liquid.
Antihistamines:
Antihistamines are over-the counter and by prescription and relieve allergy symptoms such as sneezing, runny nose, itchy nose, itchy throat, and itchy, watery and red eyes. Antihistamines work by blocking histamine from binding to cells by taking its place on the cells thereby preventing histamine from causing allergy symptoms.
Intranasal Corticosteroids:
Intranasal corticosteroids are prescription only and relieve allergy symptoms such as nasal congestion, sneezing, and itchy, runny nose. Intranasal corticosteroid sprays work by reducing inflammatory reactions caused by the immune system’s reaction to allergens, thereby stopping nasal allergy symptoms from occurring.
The next question gives some examples of these three classes of allergy relief medications and compares advantages and disadvantages of decongestants, antihistamines, and intranasal corticosteroids
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:: What are the advantages and disadvantages of commonly used
decongestants, antihistamines, and intranasal corticosteroids?
1. Decongestants:
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Nasal Spray Decongestants
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Example:
Neo-Synephrine (phenylephrine), Afrin (oxymetazoline) and others.
Advantages:
- Work quickly to relieve nasal congestion
- Various formulations approved for outdoor seasonal, indoor year-round allergy
symptoms and year-round nonallergic nasal symptoms.
Disadvantages:
- For temporary relief only.
- Requires dosing at least every 4 hours.
- Should only be used for 3 days because extended use can lead to rebound
effect (nasal stuffiness gets worse when you suddenly stop using the
medication after an extended period of using it).
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Oral Decongestants
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Example:
Sudafed (pseudoephedrine) and others.
Advantages:
- Work quickly to relieve nasal congestion.
- Once daily and twice daily dosing formulas available.
Disadvantages:
- For temporary relief only.
- Most formulas require dosing 4 to 6 times per day.
- May cause dizziness, nervousness, and sleeplessness.
- Should not be used by patients with hypertension, glaucoma, thyroid and other
diseases.
- Many potential drug interactions.
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2. Antihistamines:
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Sedating Antihistamines
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Example:
Benadryl (diphenhydramine), Chlor-Trimeton (chlorpheniramine) and others.
Advantages:
- Work quickly and effectively to relieve allergy symptoms.
- Available over-the-counter.
- Various formulations approved for outdoor seasonal, indoor year-round allergy.
Disadvantages:
- Most formulas require dosing 4 to 6 times per day.
- Frequently cause drowsiness and dizziness (diphenhydramine is actually used
as a sleep aid).
- Use with caution with alcohol or other medications that cause sedation such
as some sleep aids, tranquilizers, anti-anxiety or antidepressants.
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Non-sedating Antihistamines
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Example:
Claritin (Loratadine), Allegra (fexofenadine),
Zyrtec (Cetirizine) and others.
Advantages:
- Rarely or occasionally cause drowsiness.
- Once daily dosing.
- Claritin is available over-the-counter.
- Work quickly and can be used on an as needed basis.
- Approved for long-term use.
- Various formulations approved for outdoor seasonal and indoor year-round
allergy symptoms.
Disadvantages:
- Generally more expensive than sedating antihistamines and decongestants.
- Most formulations require a prescription.
- Use with caution with certain antifungals and antibiotics.
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3. Intranasal Corticosteroids:
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Intranasal corticosteroid sprays
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Example:
Flonase (fluticasone),
Nasonex (mometasone), and
Nasacort AQ (triamcinolone).
Advantages:
- Applied directly to nasal passages.
- Once daily dosing.
- Does not cause drowsiness or sleeplessness-nervousness seen with some
decongestants and antihistamines.
- Does not cause rebound congestion seen with decongestant sprays.
- Approved for long-term use.
- Various formulations approved for outdoor seasonal, indoor year-round allergy
symptoms and year-round non-allergic nasal symptoms.
Disadvantages:
- May take up to 2 weeks of use for maximum relief.
- Generally more expensive than sedating antihistamines and decongestants.
- Require a prescription.
- Must be used regularly for maximum benefits.
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:: What is immunotherapy?
Immunotherapy, also called allergy shots or desensitization, is usually used for patients:
- with long-term allergies (greater than 3 months per year).
- who don’t respond to allergy medications.
- who don’t tolerate medications because of side effects.
- with life-threatening allergies (such as bee-sting).
Small doses of the individual allergen such as ragweed pollen are injected regularly with gradually increasing doses until your body develops a tolerance to the ragweed pollen. Allergy shots are usually given 1 to 2 times per week for 4 to 6 months, then continued at once every 2 to 4 weeks for 2 to 5 more years. About 3 in 4 patients with seasonal allergies experience significant improvement with immunotherapy.
Immunotherapy does not cure allergies but creates an immunity to the allergen, reducing or even eliminating the symptoms of allergies.
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:: What are dust mites and what can I do reduce my exposure to
them?
House dust mites are microscopic insects that float through the air and settle into household fabrics and furnishings such as carpet, bedding, curtains and stuffed animals. Dust mites consume the microscopic particles of skin we all shed.
It is impossible to completely eliminate dust mites but the following can help limit exposure to them:
- Remove carpeting and rugs from as many areas as possible, especially bedrooms.
- Install wood, metal or plastic blinds instead of curtains in as many areas as
possible, especially bedrooms.
- Don’t keep books, toys, accessories or other items that can collect dust in your
bedroom.
- Dust and vacuum carpets, floors and curtains frequently. Use a vacuum with a
HEPA (High Efficiency Particle Arresting) filter. Have someone who doesn't have
allergies vacuum and dust when you are not in the room as it can propel allergens
into the air.
- Cover mattresses, box springs and pillows with allergen-proof covers.
- Wash bedding and children’s stuffed animals frequently in hot water (at least 130
degrees Fahrenheit).
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:: What is mold and what can I do to reduce my exposure to it?
Molds are organisms that grow in damp, dark environments. There are many types of molds, the most common household molds are alternaria and cladosporium. Molds release microscopic spores into the air which are then inhaled and can cause allergy symptoms. Molds are usually found in damp areas such as bathrooms, basements, laundry rooms, under sinks or under the refrigerator.
Follow these tips to reduce your exposure to allergenic molds:
- Regularly check all damp areas of your home for mold and clean them with a
bleach solution.
- Use air conditioners or dehumidifiers to reduce the humidity of your home.
- Keep your kitchen, bathroom and laundry room well ventilated, install a hood, air
vent or fan which vents humid air to the outside of your home.
- Dry off the shower, bathtub and the bathroom floor after showering or bathing.
- Empty and clean garbage cans daily.
- Don't put damp clothes in a laundry hamper.
- Don’t keep too many house plants in your home.
- Have your home periodically checked for roof, wall or floor leaks, especially if you
live in a rainy, humid area.
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:: How can I reduce my exposure to cockroach allergens?
Cockroach eggs, waste products and carcasses can cause allergic reactions.
Follow these tips to reduce your exposure to cockroach allergens:
- Keep your kitchen clean, wash and dry dirty dishes right after using them.
- Ensure food is kept sealed in air tight containers or kept in the refrigerator.
- Empty and clean garbage cans daily.
- Don’t save newspapers, grocery bags and cardboard boxes.
- If you see cockroaches, use pest control or hire a professional exterminator.
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:: What is pet dander and how can I reduce my exposure to it?
Dander is pet skin flakes. Proteins found in the dander and saliva of cats and dogs cause allergies. This microscopic protein is released from your pets and floats in the air you breathe. You don’t have to have direct contact with a cat or dog to be exposed to this allergen.
If you are allergic to pet allergens it is usually best to have your pet placed in a new home. Be aware that pet dander can remain in your home for several month after your pet has been relocated.
If you cannot place your cat or dog in a new home, follow these tips to reduce your exposure to pet allergens:
- Keep you pet in one area of your home or outside, avoiding the bedroom or other
areas you spend most of your time.
- Limit your direct contact with your pet and wash your hands after petting it.
- Remove carpeting and rugs from as many areas as possible, especially bedrooms.
- Install wood, metal or plastic blinds instead of curtains in as many areas as
possible, especially bedrooms.
- Consider installing an air filtering-cleaning system if you have central air
conditioning or heating to reduce the allergens that circulate through these
systems.
- Dust and vacuum carpets, floors and curtains frequently. Use a vacuum with a
HEPA (High Efficiency Particle Arresting) filter. Have someone who doesn't have
allergies vacuum and dust when you are not in the room as it can propel allergens
into the air.
- Regularly bathing and brushing your pet may or may not help reduce allergens.
Have someone who doesn't have allergies bath your pet and brush your pet
outdoors to see if it is helpful for you.
- Cover mattresses, box springs and pillows with allergen-proof covers.
- Do not put any clothes that have been worn back in the closet with clean clothes
as this can spread pet dander to your clean clothing.
- Take a shower and wash your hair every day to remove allergens from your skin
and hair.
- Keep your cat’s litter box away from main living areas. Have someone who doesn't
have allergies clean it.
- Keep your bird, mouse, hamster or other pet cage away from rooms you spend
the most time in. Have someone who doesn't have allergies clean it, preferably
outdoors.
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:: What is pollen and what can I do to reduce my exposure to it?
Pollen are the spores that plants release to propagate themselves. Pollen is responsible for triggering seasonal allergic reactions. Different regions of the country vary in the type and time of pollen release, but generally, tree pollens are usually high from early spring to midsummer, grass pollens are usually high from late spring to midsummer and weed pollens are usually high from late summer through the fall.
It is impossible to completely avoid pollen but the following tips can help limit your exposure to them:
- Monitor pollen counts in your area and try to stay indoors on peak pollen days.
The weather channel website has a tool called PollenCast where you can check
your local pollen count daily by entering your zip code. Check it out at:
http://www.weather.com/activities/health/allergies/
- Pollen levels are higher in the morning and on dry, windy days and are lower on
cool, rainy or cloudy days.
- Change your clothes, shower and wash your hair after being outdoors to wash
away pollen.
- Do not put any clothes that have been worn back in the closet with clean clothes
as this can spread pollen to your clean clothing.
- Keep your car and house windows closed during peak pollen season.
- Avoid using attic fans that draw air and pollen from outdoors. Use a cooling
system that recirculates the air inside your home.
- Don’t dry your laundry outside as pollen can settle on to it.
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* The information contained in RxPriceCheck.com is for educational purposes only and is not intended as medical advice. Consult your healthcare provider regarding your medical condition. All product names are trademarks or registered trademarks of their respective holders. View our terms of use .
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