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Monday 2 April 2012

Hay Fever

Hay Fever Overview

Hay fever, also called allergic rhinitis, upper respiratory tract allergies, and allergic conjunctivitis, is a common condition. Hay fever is caused by an abnormal immune system response to substances (called allergens) that are produced seasonally in nature and are carried through the air.
Hay fever allergy symptoms—watery, itchy eyes, congestion, allergic cough, sneezing, and runny nose—occur when the immune system overreacts to inhaled allergens and produces an antibody called immunoglobulin E (IgE). This antibody binds to cells in the body (called mast cells) and causes the release of histamine (a substance that dilates blood vessels) and other chemicals.
The most common outdoor allergens are airborne mold spores and pollen from trees, grasses, and weeds. Common indoor allergens include dust mites, animal proteins (e.g., dander, saliva), mold spores, and cockroach secretions (e.g., fecal matter, saliva).

Incidence and Prevalence of Hay Fever

According to the American Academy of Allergy, Asthma & Immunology (AAAAI), more than 35 million people in the United States (15–20% of the population) are affected by hay fever allergies. The Asthma and Allergy Foundation of America reports that hay fever is the fifth leading chronic condition in the United States and the third most common chronic condition in children and adolescents younger than age 18. Outdoor and seasonal allergies account for more than half of all allergy-related medical appointments.

Sinus Allergies & Sinusitis

Nasal and sinus allergies result from an immune system reaction to allergens (e.g., pollen, mold) that enter the respiratory system through the body's airways, producing a response similar to an upper respiratory infection (cold virus).

White blood cells (leukocytes) mark the allergens as intruders and produce secretions that cause the nasal lining to swell, helping to combat the invading substances. The resulting sinus allergy symptoms—sneezing; allergic cough; watery, itchy eyes; and nasal symptoms (e.g., nasal congestion)—are the same symptoms produced by the common cold.

Since the symptoms of sinus allergies and colds are similar, chronic nose allergy sufferers often misidentify hay fever (allergic rhinitis) as a sinus cold. In most cases, this confusion is harmless, because sinus colds respond to the same treatment as allergies. Common sinus allergy remedies (e.g., antihistamines, nasal sprays) often work well for both sinus allergies and sinus colds, reducing swelling and providing nasal congestion relief.

In some cases, however, a cold virus causes inflammation and swelling in the mucosal membranes of the sinuses, limiting sinus drainage. Mucus then becomes trapped in the sinuses and results in sinus blockage, which allows bacteria that are present in the upper respiratory system (e.g., Streptococcus pneumonia, Haemophilus influenzae, pneumococci, staphylococci) to multiply and causing a sinus infection (sinusitis).

Each year in the United States, sinusitis affects about 15% of the population and compels 30 million people to seek treatment. In one-third of cases, sinusitis develops after an upper respiratory infection.
Once acute sinusitis sets in, additional symptoms include the following:
  • Intense sinus pressure
  • Headache
  • Green or yellow nasal discharge
  • Pain and tenderness behind the affected sinuses (e.g., behind the eyes, cheeks, or forehead)
There are a number of ways to treat sinusitis. Treatment approaches include sinus irrigation, in which a sinus rinse is used to flush the sinuses and nasal passages, and using warm mist humidifiers, which add moisture to the air. Staying well hydrated (e.g., by drinking plenty of fluids) can help decrease the thick mucus trapped in the sinuses and provide nasal relief by encouraging sinus drainage.
Over-the-counter sinus medication (e.g., decongestants, antihistamines) can be used to reduce sinus pressure and encourage sinus drainage. Analgesics (e.g., ibuprofen) can help relieve discomfort and provide overall nasal relief for both sinusitis and regular sinus allergies.

When symptoms persist or worsen, consultation with a family physician or an otolaryngologist (ear, nose, and throat [ENT] doctor) may be necessary. Prescription treatments include antibiotics to fight bacterial infection and steroid nasal sprays to reduce inflammation. Chronic sinus problems may also be treated surgically.

Perennial Allergies

Hay fever is one of several types of allergies that cause similar allergy symptoms. Itchy eyes (allergic conjunctivitis), nasal congestion, excess mucus, and difficulty breathing are common symptoms in people with hay fever, as well as other allergic conditions. Wheezing, dark eye circles, and allergic cough may be caused by a seasonal allergy to high pollen levels (as is the case with hay fever) or to year round substances (e.g., pet allergies, dust mite allergies, mold allergies).

Pet Allergies

Pet allergies are very common and result when people inherit or develop a hypersensitivity to animal saliva, dander (such as cat dander), or urine. These substances, known as allergens when they cause an allergic reaction, are sticky and have a tendency to collect on surfaces in the home and elsewhere. When a person who has a pet allergy comes in contact with these allergens, allergy symptoms such as swollen, itchy eyes, nasal congestion, and difficult breathing develop within several hours.

A doctor or allergist can diagnose a pet allergy, often through a scratch test, in which a small amount of the suspected pet allergen is introduced under the skin. Unlike hay fever allergies, pet allergies are simple to treat (or extremely difficult to cope with, depending on your perspective), because removing the pet and cleaning existing dander from the surfaces of the home generally clears allergy symptoms and provides significant allergy relief.

Dust Mites Allergies

Dust mites are are very small arthropods (related to ticks and spiders) that live abundantly in dust. They survive by consuming minute particles of organic matter, including skin cells and other materials that are typically found in homes and other dwellings.

Dust mite's bodies are made of chitin, which is an allergenic substance, and their partially digested food and fecal matter (dust mite dander) are allergenic as well. Allergic response to the creatures is common, so common in fact, that as much as 10% of the population is sensitive to them and experiences some type of sinus allergy. Relief and overall allergy care for people with dust mite allergies usually focuses on environmental interventions in the home.

Since dust mites live in and consume the substances in dust, it makes sense to seek allergy relief by ridding the home of as much dust as possible. However, unlike the sticky allergens found in, for example, cat dander, the dust that carries dust mites is easily stirred into the air, potentially making allergies worse. It may take repeated, rigorous cleaning, preferably with a vacuum cleaner equipped with an allergan air filter to significantly reduce the presence of dust mites.

For severe infestations, chemicals are available that provide allergy relief by killing dust mites or by inactivating dust mite allergens. Tannic acid, sprayed on carpets or upholstered furniture, is effective in destroying dust mite allergens, but does not kill the mites. Benzyl benzoate, a substance that is sold as a food flavoring agent, does kill them.

While products such as dust mite covers, which are designed to be placed on top of bedding, claim to shield people from dust mites, a study published in The New England Journal of Medicine found that dust mite covers are unlikely to have an effect on typical allergy symptoms, and are not a worthwhile investment in allergy relief or allergy care.

Mold Allergies

Mold is a type of fungus that develops in homes and other dwellings when provided with sufficient moisture, warmth, and a surface area on which to grow. Mold produces spores that become airborne allergens and attach themselves to dust. When the dust is inhaled by a person who is sensitive to mold, allergy symptoms develop.

There are a few dozen commonly found molds that are highly allergenic to people. While mold allergies are seasonal in origin, usually peaking mid to late summer, molds are considered a perennial sinus allergy because unlike seasonal pollens, they can live for a long time and only become dormant in cold weather.

Since mold requires moisture to become active, keeping the home dry can help keep mold that is present dormant. Water leaks, wet floors, and moist refrigerators are typical breeding grounds for mold so these should be cleaned and dried out as soon as possible.

Molds consume organic matter, so items such as paper and clothing should be kept dry. Allergy relief from mold allergies can often be achieved by eliminating the conditions in which mold spores flourish. Mold can be destroyed with regular vacuuming and cleaning, and rugs that harbor mold should be laundered regularly. For severe infestations, advice from a mold expert can be helpful.

Unlike hay fever allergens, which can be monitored by the pollen forecast, but are otherwise beyond our control and nearly impossible to avoid, allergy relief from these perennial allergies often can be achieved through simple, non-medical allergy care, as long as the culprit is identified. A family physician or allergist can help determine the cause for perennial allergies and provide a significant level of allergy relief.


Hay Fever in Children & Teens

Symptoms of Hay Fever

For hay fever caused by grass, tree, and ragweed pollens, symptoms occur seasonally—typically from spring to mid-September. Other hay fever allergens are present year-round, in which case symptoms can occur anytime, indoors or out. Symptoms of a hay fever attack include.
Hay Fever in Children article - Masterfile
  • Persistent sneezing, runny nose (usually with a clear discharge), and swollen nasal passages
  • Red, itchy, watery eyes
  • A dry itchy throat (or roof of the mouth), itchy skin, and wheezing
  • Headaches also often develop, perhaps due to congested sinuses

What Is Hay Fever?

Hay fever is a misnomer: it’s not usually caused by hay and does not produce a fever. Rather, it is an allergic reaction that occurs in your eyes, nose, and throat. The proper name is allergic rhinitis, and it’s thought that more than 35 million people in the United States and Canada—people of all ages—are affected by it.

According to the American Academy of Allergy, Asthma and Immunology (AAAAI), Americans lose 3.5 million workdays annually because of this condition.

Seasonal hay fever is generally caused by airborne pollens and outdoor mold spores that proliferate in warm weather, from spring to fall. Perennial hay fever, triggered by such allergens as household dust, animal dander, hair, fur, dog saliva, feathers, or mold spores, can flare up at any time of the year.


What Causes Hay Fever?

It’s your own immune system reacting to irritants, or allergens, that causes the runny nose and other symptoms of hay fever. It’s not clear why some people are sensitive to specific allergens. But when an allergen enters the nose, throat, or eyes of someone who is susceptible to it, the body responds first by developing a sensitivity to it, then, upon further exposures, by releasing illness-fighting histamines and other inflammatory compounds (designed to fight off this foreign “invader”) into the affected areas. The resulting inflammation of the mucous membranes produces the symptoms of hay fever.

A number of different irritants, or allergens, can trigger rhinitis—and they vary from person to person. Ragweed, grass, and tree pollens are the worst culprits, along with mold spores. Flower pollens are too heavy to be airborne (bees carry them), so they are seldom a cause of hay fever. Grass and tree pollens become airborne in spring—the first allergy season each year. Ragweed gets going in the late summer and early fall (except on the West Coast, where it is less common), followed by an upsurge of molds and fungi that live in decomposing leaves.

Many molds are present year-round, indoors and out. Some allergies are triggered by animal dander (actually a protein in the animal’s saliva, which is transferred to the fur during grooming and then dries and sheds with the dander), feathers, cosmetics, cigarette smoke, and dust mites, as well as other indoor pollutants. Dust mites peak in warm, humid weather.


What If You Do Nothing about Hay Fever?

As long as the allergens remain present, and you remain sensitive to them, you can have attacks.


Home Remedies for Hay Fever

The most effective treatment is to eliminate the cause of your discomfort (see Prevention). If you can’t, antihistamines may help. If your allergies are not severe, try one of the over-the-counter antihistamines, which may help control symptoms; a decongestant may also bring relief. The drawback is that most antihistamines cause drowsiness. Several effective nonsedating antihistamines are available by prescription only. These are less likely to cause drowsiness, but if you want to use them, be sure to talk to your doctor or pharmacist about possible interactions these drugs can have with other medications.

Try to avoid using over-the-counter decongestants; these products may provide temporary relief, but over the long haul cause the nasal passages to swell more than ever—a response known as the rebound effect.

 

Prevention of Hay Fever

  • Pinpoint the allergy. The first step in controlling, maybe preventing, hay fever is to find out what you are allergic to. Maybe you know already, from years of experience, that it’s grass pollen in early spring or ragweed in the fall. If you don’t know, you should see your physician to help diagnose the allergen that triggers your symptoms. If your problem is feathers, animal dander, or a cosmetic, you will probably be able to avoid hay fever entirely.
  • Stay informed about pollen counts. If it’s pollen that bothers you, you’ll be interested to hear that the AAAAI now sponsors a nationwide network that collects and broadcasts more accurate pollen counts. Various collecting stations all over the country do pollen and mold counts up to three days a week, which are then faxed to the AAAAI, which in turn faxes them to radio stations and newspapers. The counts are given either numerically or described as “absent,” “low,” “moderate,” “high,” and “very high.” According to the AAAAI, there’s no accurate way to forecast pollen counts. But if you hear that pollen counts have risen, you can at least carry medication when you leave the house or postpone outdoor activity until things clear up.
  • Stay indoors on bad days. When pollen counts are high, people with severe allergies should stay indoors if possible, especially between 5 am and 10 am, when pollens are most prevalent. Use an air conditioner if you have one. Be sure you keep the filters clean or you may end up blowing allergens around. You may be surprised to learn that a dog or cat that goes in and out of the house can carry pollen indoors, so try to avoid contact with pets if they have been outdoors.
  • If you do go outdoors, wash your hair afterwards. Washing your hair after spending time outside when the pollen count is high will remove pollen and thus may prevent a nighttime sneezing attack caused by pollen that falls from your hair onto the pillow.
  • Try the nasal spray Nasalcrom. Available over the counter, Nasalcrom is considered a safe and effective medication for preventing hay fever symptoms.
  • Check your car’s air conditioner. Just like home air conditioning, your car’s AC system can help reduce your exposure to allergens. But if your car’s air conditioner seems to be making you sneeze, the culprits are probably fungi that produce airborne spores and grow deep within the air-conditioning system. To minimize the problem, keep the car windows open part way for 10 minutes after you turn on the AC. Don’t direct the vents toward your face. If these steps don’t help, have your car treated with a disinfectant registered with the Environmental Protection Agency (EPA), available at car dealer service departments, some service stations, and most auto AC shops.
  • Most air purifiers aren’t helpful. The few controlled studies on air-purifying machines have found that they have little, if any, effect on allergens. Very small air cleaners cannot remove dust and pollen. Electrostatic precipitators, which electrically charge airborne particles and use polarized metal plates to pull them out of the air, can pollute indoor air with ozone, aggravating allergy symptoms. The best type of filter is the HEPA (high-efficiency particulate arresting)—effective but expensive.
  • Avoid smoke and other irritants. In addition to not smoking, you should also avoid smoky environments. Insect sprays, fresh paint, and other households chemicals can also be irritating.
  • “Allergy-proof” your house. If you’re allergic to dust and dust mites, take steps to combat them. Remove some or all carpets and soft furnishings. Keep floors and furniture dust-free. Get rid of feather pillows; use synthetic materials instead. Enclose your mattress in a plastic casing. Wash clothing frequently. If you’re allergic to your pet, the best remedy is to find another home for it. If that is out of the question, at least try to keep the pet out of your bedroom.
  • Get assistance. If molds and fungi set you off, get somebody else to do your yard cleanup in the fall.


When To Call Your Doctor about Hay Fever

In itself, hay fever is not a serious health problem and doesn’t cause any permanent harm. But to alleviate it, you need to find out what you are allergic to. If you don’t know, you should see a physician, who may be able to determine what triggers your attacks. You should also call a doctor if any type of secondary infection develops in your sinus cavities—signaled by pain, fever, a green or yellow discharge, or tenderness in the sinus areas or the teeth.

What Your Doctor Will Do

Your doctor will want a history of symptoms and a family history of known allergies, and will also ask about hobbies or work that may cause exposure to allergens. You may be referred to an allergy specialist. A physical examination of the upper respiratory tract will be made. If allergic rhinitis is suspected, skin tests will be made to confirm it. A blood sample may be taken and examined for antibodies, which in some cases can be helpful in determining treatment.

If symptoms are severe, an allergy specialist may also recommend allergy shots. These desensitize you to specific allergens and eventually allow your body to tolerate them. Many people—children as well as adults—find the shots really do reduce symptoms. And it’s not always necessary to repeat them annually.

For More Information about Hay Fever

  • American Academy of Allergy, Asthma & Immunology
  • Asthma and Allergy Foundation of America
Publication Review By: the Editorial Staff at HealthCommunities.com
Published: 10 Aug 2010
Last Modified: 02 Jun 2011

http://www.healthcommunities.com/hay-fever/overview-of-hay-fever.shtml