An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are

• Pollen
• Dust mites
• Mold spores
• Pet dander
• Food
• Insect stings
• Medicines

Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm. Genes and the environment probably both play a role.

Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Allergies can range from minor to severe. Anaphylaxis is a severe reaction that can be life-threatening. Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions.

Asthma is one of our nation's most common chronic health conditions. Many substances can aggravate allergies or increase the severity of asthma symptoms in individuals who are sensitive to these allergens or irritants.

This content is designed to help you survive the seasons by providing information on asthma, allergies and some of the most common seasonal and non-seasonal allergens and asthma irritants such as:

• Cigarette Smoke
• Cockroaches
• Dust Mites
• Pets & Animals
• Pollen

In addition, we provide preventive strategies for each to help you avoid exposure to these substances.

Please remember that information contained on this Web site is provided for educational and informational purposes only and should not be used to guide the diagnosis or treatment of any medical condition without the advice and supervision of a licensed, qualified health care provider.

Cigarette Smoke

Cigarette smoke contains a number of toxic chemicals and irritants. People with allergies may be more sensitive to cigarette smoke than others and research studies indicate that smoking may aggravate allergies.

Smoking does not just harm smokers but also those around them. Research has shown that children and spouses of smokers tend to have more respiratory infections and asthma than those of non-smokers. In addition, exposure to secondhand smoke can increase the risk of allergic complications such as sinusitis and bronchitis .

Common symptoms of smoke irritation are burning or watery eyes, nasal congestion, coughing, hoarseness and shortness of breath presenting as a wheeze.

Preventive Strategies

• Don't smoke and if you do, seek support to quit smoking.
• Seek smoke-free environments in restaurants, theaters and hotel rooms.
• Avoid smoking in closed areas like homes or cars where others may be exposed to second-hand smoke.

Cockroaches

Cockroaches are one of the most common and allergenic of indoor pests. Recent studies have found a strong association between the presence of cockroaches and increases in the severity of asthma symptoms in individuals who are sensitive to cockroach allergens. These pests are common even in the cleanest of crowded urban areas and older dwellings. They are found in all types of neighborhoods.

The proteins found in cockroach saliva are particularly allergenic but the body and droppings of cockroaches also contain allergenic proteins.

Preventive Strategies

• Keep food and garbage in closed, tight-lidded containers. Never leave food out in the kitchen.
• Do not leave out pet food or dirty food bowls.
• Eliminate water sources that attract these pests, such as leaky faucets and drain pipes.
• Mop the kitchen floor and wash countertops at least once a week.
• Plug up crevices around the house through which cockroaches can enter.
• Limit the spread of food around the house and especially keep food out of bedrooms.
• Use bait stations and other environmentally safe pesticides to reduce cockroach infestation.

Dust Mites

Dust mites are tiny microscopic relatives of the spider and live on mattresses, bedding, upholstered furniture, carpets and curtains. These tiny creatures feed on the flakes of skin that people and pets shed daily and they thrive in warm and humid environments. No matter how clean a home is, dust mites cannot be totally eliminated. However, the number of mites can be reduced by following the suggestions below.

Preventive Strategies

• Use a dehumidifier or air conditioner to maintain relative humidity at about 50% or below.
• Encase your mattress and pillows in dust-proof or allergen impermeable covers (available from specialty supply mail order companies, bedding and some department stores).
• Wash all bedding and blankets once a week in hot water (at least 130 - 140°F) to kill dust mites. Non-washable bedding can be frozen overnight to kill dust mites.
• Replace wool or feathered bedding with synthetic materials and traditional stuffed animals with washable ones.
• If possible, replace wall-to-wall carpets in bedrooms with bare floors (linoleum, tile or wood) and remove fabric curtains and upholstered furniture.
• Use a damp mop or rag to remove dust. Never use a dry cloth since this just stirs up mite allergens .
• Use a vacuum cleaner with either a double-layered microfilter bag or a HEPA filter to trap allergens that pass through a vacuum's exhaust.
• Wear a mask while vacuuming to avoid inhaling allergens, and stay out of the vacuumed area for 20 minutes to allow any dust and allergens to settle after vacuuming.

Pets & Animals

Many people think animal allergies are caused by the fur or feathers of their pet. In fact, allergies are actually aggravated by:

• proteins secreted by oil glands and shed as dander
• proteins in saliva (which stick to fur when animals lick themselves)
• aerosolized urine from rodents and guinea pigs

Keep in mind that you can sneeze with and without your pet being present. Although an animal may be out of sight, their allergens are not. This is because pet allergens are carried on very small particles. As a result pet allergens can remain circulating in the air and remain on carpets and furniture for weeks and months after a pet is gone. Allergens may also be present in public buildings, schools, etc. where there are no pets.

Preventive Strategies

• Remove pets from your home if possible.
• If pet removal is not possible, keep them out of bedrooms and confined to areas without carpets or upholstered furniture.
• If possible, bathe pets weekly to reduce the amount of allergens.
• Wear a dust mask and gloves when near rodents.
• After playing with your pet, wash your hands and clean your clothes to remove pet allergens.
• Avoid contact with soiled litter cages.
• Dust often with a damp cloth.

Ragweed Pollen

Ragweed and other weeds such as curly dock, lambs quarters, pigweed, plantain, sheep sorrel and sagebrush are some of the most prolific producers of pollen allergens. Although the ragweed pollen season runs from August to November, ragweed pollen levels usually peak in mid-September in many areas in the country.

In addition, pollen counts are highest between 5:00 a.m. - 10:00 a.m. and on dry, hot and windy days.

Preventive Strategies

• Avoid the outdoors between 5:00 a.m. - 10:00 a.m. Save outside activities for late afternoon or after a heavy rain, when pollen levels are lower.
• Keep windows in your home and car closed to lower exposure to pollen. To keep cool, use air conditioners and avoid using window and attic fans.
• Be aware that pollen can also be transported indoors on people and pets.
• Dry your clothes in an automatic dryer rather than hanging them outside. Otherwise pollen can collect on clothing and be carried indoors.

Grass Pollen

As with tree pollen, grass pollen is regional as well as seasonal. In addition, grass pollen levels can be affected by temperature, time of day and rain.

Of the 1,200 species of grass that grow in North America, only a small percentage of these cause allergies. The most common grasses that can cause allergies are:

• Bermuda grass
• Johnson grass
• Kentucky bluegrass
• Orchard grass
• Sweet vernal grass
• Timothy grass

Preventive Strategies:

• If you have a grass lawn, have someone else do the mowing. If you must mow the lawn yourself, wear a mask.
• Keep grass cut short.
• Choose ground covers that don't produce much pollen, such as Irish moss, bunch, and dichondra.
• Avoid the outdoors between 5:00 a.m. - 10:00 a.m. Save outside activities for late afternoon or after a heavy rain, when pollen levels are lower.
• Keep windows in your home and car closed to lower exposure to pollen. To keep cool, use air conditioners and avoid using window and attic fans.
• Be aware that pollen can also be transported indoors on people and pets.
• Dry your clothes in an automatic dryer rather than hanging them outside. Otherwise pollen can collect on clothing and be carried indoors.

Tree Pollen

Trees can aggravate your allergy whether or not they are on your property, since trees release large amounts of pollen that can be distributed miles away from the original source. Trees are the earliest pollen producers, releasing their pollen as early as January in the Southern states and as late as May or June in the Northern states.

Most allergies are specific to one type of tree such as:

• catalpa
• elm
• hickory
• olive
• pecan
• sycamore
• walnut

or to the male cultivar of certain trees. The female of these species are totally pollen-free:

• ash
• box elder
• cottonwood
• date palm
• maple (red)
• maple (silver)
• Phoenix palm
• poplar
• willow

Some people, though, do show cross-reactivity among trees in the alder, beech, birch and oak family, and the juniper and cedar family.

Preventive Strategies

• If you buy trees for your yard, look for species that do not aggravate allergies such as crape myrtle, dogwood, fig, fir, palm, pear, plum, redbud and redwood trees or the female cultivars of ash, box elder, cottonwood, maple, palm, poplar or willow trees.
• Avoid the outdoors between 5:00 a.m. - 10:00 a.m. Save outside activities for late afternoon or after a heavy rain, when pollen levels are lower.
• Keep windows in your home and car closed to lower exposure to pollen. To keep cool, use air conditioners and avoid using window and attic fans.
• Be aware that pollen can also be transported indoors on people and pets.
• Dry your clothes in an automatic dryer rather than hanging them outside. Otherwise pollen can collect on clothing and be carried indoors.

An allergy blood test measures a substance called immunoglobulin E (IgE) in your blood. IgE is an antibody that your body makes. If you have allergies, you may have more IgE in your blood than normal.

Allergies are a common, long-term condition that involves your immune system. Your immune system makes antibodies to fight off viruses, bacteria, and other things that can make you sick. With allergies, your immune system treats one or more harmless substances, such as pollen or peanuts, as a threat. To fight the "threat," your immune system makes IgE antibodies. This is what causes your allergy symptoms.

Harmless substances that may cause allergies are called allergens. Common allergens include:

• Pollen
• Dust
• Mold
• Animal dander
• Certain foods, including nuts and shellfish
• Certain medicines, such as penicillin.

Allergy symptoms depend on the type of allergy you have. They can range from itching and sneezing to asthma or a life-threatening condition called anaphylactic shock.

Other names: IgE allergy test, Quantitative IgE, Immunoglobulin E, Total IgE, Specific IgE, RAST, CAP, ELISA

You’re feeling pretty lousy. You’ve got sniffles, sneezing, and a sore throat. Is it a cold, flu, or allergies? It can be hard to tell them apart because they share so many symptoms. But understanding the differences will help you choose the best treatment.

“If you know what you have, you won’t take medications that you don’t need, that aren’t effective, or that might even make your symptoms worse,” says NIH’s Dr. Teresa Hauguel, an expert on infectious diseases that affect breathing.

Cold, flu, and allergy all affect your respiratory system, which can make it hard to breathe. Each condition has key symptoms that set them apart.

Colds and flu are caused by different viruses. “As a rule of thumb, the symptoms associated with the flu are more severe,” says Hauguel. Both illnesses can lead to a runny, stuffy nose; congestion; cough; and sore throat. But the flu can also cause high fever that lasts for 3-4 days, along with a headache, fatigue, and general aches and pain. These symptoms are less common when you have a cold.

“Allergies are a little different, because they aren’t caused by a virus,” Hauguel explains. “Instead, it’s your body’s immune system reacting to a trigger, or allergen, which is something you’re allergic to.” If you have allergies and breathe in things like pollen or pet dander, the immune cells in your nose and airways may overreact to these harmless substances. Your delicate respiratory tissues may then swell, and your nose may become stuffed up or runny.

“Allergies can also cause itchy, watery eyes, which you don’t normally have with a cold or flu,” Hauguel adds.

Allergy symptoms usually last as long as you’re exposed to the allergen, which may be about 6 weeks during pollen seasons in the spring, summer, or fall. Colds and flu rarely last beyond 2 weeks.

Most people with a cold or flu recover on their own without medical care. But check with a health care provider if symptoms last beyond 10 days or if symptoms aren’t relieved by over-the-counter medicines.

To treat colds or flu, get plenty of rest and drink lots of fluids. If you have the flu, pain relievers such as aspirin, acetaminophen, or ibuprofen can reduce fever or aches. Allergies can be treated with antihistamines or decongestants. See the “Wise Choices” box for more details.

Be careful to avoid “drug overlap” when taking medicines that list 2 or more active ingredients on the label. For example, if you take 2 different drugs that contain acetaminophen—one for a stuffy nose and the other for headache—you may be getting too much acetaminophen.

“Read medicine labels carefully—the warnings, side effects, dosages. If you have questions, talk to your doctor or pharmacist, especially if you have children who are sick,” Hauguel says. “You don’t want to overmedicate, and you don’t want to risk taking a medication that may interact with another.”

Cold, Flu, or Allergy?

Treatment depends on which you have. A health professional can help you choose the best therapy.

Common Cold

• Symptoms last up to 2 weeks
• Stuffy, runny nose; sore throat; cough
• Treated with rest, fluids, over-the-counter (OTC) medicines to ease symptoms

Seasonal Flu

• Symptoms usually last 1-2 weeks
• High fever (100-102 °F, or higher in youngsters), headache, aches and pains, weakness, exhaustion, cough, chest discomfort
• Treated with rest, fluids, OTC medicines, prescription antiviral drugs

Airborne Allergy

• Lasts as long as allergens (such as pollen, pet dander) are present
• Stuffy, runny nose; itchy, watery eyes
• Treated with antihistamines, decongestants, nasal steroids

Seasonal allergies, also called hay fever or allergic rhinitis, are triggered each spring, summer, and fall when trees, weeds, and grasses release pollen into the air. When the pollen ends up in your nose and throat, it can bring on sneezing, runny nose, coughing, and itchy eyes and throat. People manage seasonal allergies by taking medication, avoiding exposure to the substances that trigger their allergic reactions, or having a series of “allergy shots” (a form of immunotherapy).

People also try various complementary approaches to manage their allergies. If you are considering any complementary health approach for the relief of seasonal allergy symptoms, here are some things you need to know.

1. Nasal saline irrigation. There is some good evidence that saline nasal irrigation (putting salt water into one nostril and draining it out the other) can be useful for modest improvement of allergy symptoms. Nasal irrigation is generally safe; however, neti pots and other rinsing devices must be used and cleaned properly. According to the U.S. Food and Drug Administration, tap water that is not filtered, treated, or processed in specific ways is not safe for use as a nasal rinse.
2. Butterbur extract. There are hints that the herb butterbur may decrease the symptoms associated with nasal allergies. However, there are concerns about its safety.
3. Honey. Only a few studies have looked at the effects of honey on seasonal allergy symptoms, and there is no convincing scientific evidence that honey provides symptom relief. Eating honey is generally safe; however, children under 1 year of age should not eat honey. People who are allergic to pollen or bee stings may also be allergic to honey.
4. Acupuncture. A 2015 evaluation of 13 studies of acupuncture for allergic rhinitis, involving a total of 2,365 participants, found evidence that this approach may be helpful.
5. Probiotics. There is some evidence that suggests that probiotics may improve some symptoms, as well as quality of life, in people with allergic rhinitis, but because probiotic formulations vary from study to study, it’s difficult to make firm conclusions about its effectiveness.
6. Talk to your health care provider. If you suffer from seasonal allergies and are considering a complementary health approach, talk to your health care provider about the best ways to manage your symptoms. You may find that when the pollen count is high, staying indoors, wearing a mask, or rinsing off when you come inside can help.

A change in season can brighten your days with vibrant new colors. But blooming flowers and falling leaves can usher in more than beautiful backdrops. Airborne substances that irritate your nose can blow in with the weather. When sneezing, itchy eyes, or a runny nose suddenly appears, allergies may be to blame.

Allergies arise when the body’s immune system overreacts to substances, called allergens, that are normally harmless. When a person with allergies breathes in allergens—such as pollen, mold, pet dander, or dust mites—the resulting allergic reactions in the nose are called allergic rhinitis, or hay fever.

Allergy is one of the most common long-term health conditions. “Over the past several decades, the prevalence of allergies has been increasing,” says Dr. Paivi Salo, an allergy expert at NIH. “Currently, airborne allergies affect approximately 10-30% of adults and 40% of children.”

Avoiding your allergy triggers is the best way to control your symptoms. But triggers aren’t always easy to identify. Notice when and where your symptoms occur. This can help you figure out the cause.

“Most people with allergies are sensitive to more than one allergen,” Salo explains. “Grass, weed, and tree pollens are the most common causes of outdoor allergies.” Pollen is often the source if your symptoms are seasonal. Indoor allergens usually trigger symptoms that last all year.

If your symptoms become persistent and bothersome, visit your family physician or an allergist. They can test for allergy sensitivities by using a skin or blood test. The test results, along with a medical exam and information about when and where your symptoms occur, will help your doctor determine the cause.

Even when you know your triggers, avoiding allergens can be difficult. When pollen counts are high, stay inside with the windows closed and use the air conditioning. Avoid bringing pollen indoors. “If you go outside, wash your hair and clothing,” Salo says. Pets can also bring in pollen, so clean them too.

For indoor allergens, keep humidity levels low in the home to keep dust mites and mold under control. Avoid upholstered furniture and carpets because they harbor allergens. Wash your bedding in hot water, and vacuum the floors once a week.

Allergies run in families. Your children’s chances of developing allergies are higher if you have them. While there’s no “magic bullet” to prevent allergies, experts recommend breast feeding early in life. “Breast milk is the least likely to trigger allergic reactions, it’s easy to digest, and it strengthens an infant’s immune system,” Salo says.

Sometimes, avoiding allergens isn’t possible or isn’t enough. Untreated allergies are associated with chronic conditions like sinus infections and asthma. Over-the-counter antihistamines, nasal sprays, and decongestants can often ease mild symptoms. Prescription medications and allergy shots are sometimes needed for more severe allergies. Talk with your doctor about treatment options.

Allergy relief can help clear up more than just itchy, watery eyes. It can allow you to breathe easy again and brighten your outlook on seasonal changes.

Allergy Symptoms

• Runny or stuffy nose
• Sneezing
• Itchy nose, eyes, ears, and mouth
• Red and watery eyes
• Swelling around the eyes
• Coughing
• Wheezing
• Chest tightness
• Shortness of breath

Children are magnets for colds. But when the sniffles and sneezing won’t go away for weeks, the culprit may be allergies.

Long-lasting sneezing, with a stuffy or runny nose, may signal the presence of allergic rhinitis—the collection of symptoms that affect the nose when you have an allergic reaction to something you breathe in and that lands on the lining inside the nose.

Allergies may be seasonal or can strike year-round (perennial). In most parts of the United States, plant pollens are often the cause of seasonal allergic rhinitis—more commonly called hay fever. Indoor substances, such as mold, dust mites, and pet dander, may cause the perennial kind.

Up to 40 percent of children suffer from allergic rhinitis. And children are more likely to develop allergies if one or both parents have allergies.

The U.S. Food and Drug Administration (FDA) regulates over-the-counter (OTC) and prescription medicines that offer allergy relief as well as allergen extracts used to diagnose and treat allergies. Take care to read and follow the directions provided when giving any medicine to children, including these products.

Immune System Reaction

An allergy is the body’s reaction to a specific substance, or allergen. Our immune system responds to the invading allergen by releasing histamine and other chemicals that typically trigger symptoms in the nose, lungs, throat, sinuses, ears, eyes, skin, or stomach lining.

In some children, allergies can also trigger symptoms of asthma—a disease that causes wheezing or difficulty breathing. If a child has allergies and asthma, “not controlling the allergies can make asthma worse,” says Anthony Durmowicz, M.D., a pediatric pulmonary doctor at the FDA.

Avoid Pollen, Mold and Other Allergy Triggers

If your child has seasonal allergies, pay attention to pollen counts and try to keep your child inside when the levels are high.

• In the late summer and early fall, during ragweed pollen season, pollen levels are highest in the morning.
• In the spring and summer, during the grass pollen season, pollen levels are highest in the evening.
• Some molds, another allergy trigger, may also be seasonal. For example, leaf mold is more common in the fall.
• Sunny, windy days can be especially troublesome for pollen allergy sufferers.

It may also help to keep windows closed in your house and car and run the air conditioner.

Allergy Medicines for Children

For most children, symptoms may be controlled by avoiding the allergen, if known, and using OTC medicines. But if a child’s symptoms are persistent and not relieved by OTC medicines, see a health care professional.

Although some allergy medicines are approved for use in children as young as 6 months, the FDA cautions that simply because a product’s box says that it is intended for children does not mean it is intended for children of all ages. Always read the label to make sure the product is right for your child’s age.

When your child is taking more than one medication, read the label to be sure that the active ingredients aren’t the same. Although the big print may say the product is to treat a certain symptom, different products may have the same medicine (active ingredient). It might seem that you are buying different products to treat different symptoms, but in fact the same medicine could be in all the products. The result: You might accidently be giving too much of one type of medicine to your child.

Children are more sensitive than adults to many drugs. For example, some antihistamines can have adverse effects at lower doses on young patients, causing excitability or excessive drowsiness.

Allergy Shots and Children

Jay E. Slater, M.D., a pediatric allergist at the FDA, says that children who don’t respond to either OTC or prescription medications, or who suffer from frequent complications of allergic rhinitis, may be candidates for allergen immunotherapy—commonly known as allergy shots.

After allergy testing, typically by skin testing to detect what allergens your child may react to, a health care professional injects the child with “extracts”—small amounts of the allergens that trigger a reaction. The doses are gradually increased so that the body builds up immunity to these allergens. Allergen extracts are manufactured from natural substances, such as pollens, insect venoms, animal hair, and foods. More than 1,200 extracts are licensed by the FDA.

In 2014, the FDA approved three new immunotherapy products that are taken under the tongue for treatment of hay fever caused by certain pollens, two of them for use in children. All of them are intended for daily use, before and during the pollen season. They are not meant for immediate symptom relief. Although they are intended for at-home use, these are prescription medications, and first doses are taken in the presence of a health care provider. The products are Oralair, Grastek, and Ragwitek (which is approved for use in adults only).

In 2017, the FDA approved Odactra, the first immunotherapy product administered under the tongue for treatment of house dust mite induced allergic rhinitis (nasal inflammation) with or without conjunctivitis (eye inflammation). Odactra is approved for use only in adults.

“Allergy shots are never appropriate for food allergies,” adds Slater, “but it’s common to use extracts to test for food allergies so the child can avoid those foods.”

“In the last 20 years, there has been a remarkable transformation in allergy treatments,” says Slater. “Kids used to be miserable for months out of the year, and drugs made them incredibly sleepy. But today’s products offer proven approaches for relief of seasonal allergy symptoms.”

Histamine is a signaling molecule, sending messages between cells. It tells stomach cells to make stomach acid. And it helps our brain stay awake. You may have seen these effects illustrated by medicines that block histamine. Some antihistamines can make us sleepy and other antihistamines are used to treat acid reflux.

Histamine also works with our immune system.

It helps protect us from foreign invaders. When the immune system discovers an invader, immune cells called B-cells make IgE antibodies. The IgE’s are like “WANTED” signs that spread throughout the body, telling other immune cells about specific invaders to look for.

Eventually mast cells and basophils pick up the IgE’s and become sensitized. When they come in contact with a target invader…They spew histamine and other inflammatory chemicals.

Blood vessels become leakier, so that white blood cells and other protective substances can sneak through and fight the invader.

Histamine’s actions are great for protecting the body against parasites.

But with allergies, the immune system overreacts to harmless substances, not parasites. This is when histamine becomes our foe. Common allergens include peanuts, pollen, and animal dander.

Leaky vessels cause tearing in eyes, congestion in the nose, and swelling...basically anywhere. Histamine works with nerves to produce itching. In food allergies it can cause vomiting and diarrhea. And it constricts muscles in the lungs, making it harder to breathe.

Most worrisome is when histamine causes anaphylaxis, a severe reaction that is potentially fatal. Swollen airways can prevent breathing, and a rapid drop in blood pressure could starve organs of vital blood.

So what can be done about histamine?

Antihistamines block cells from seeing histamine and can treat common allergies. Medicines like steroids can calm the inflammatory effects of allergies. And anaphylaxis needs to be treated with a shot of epinephrine, which opens up airways, and increases blood pressure.

So our relationship with histamine is…complicated. We can do better.