Hay Fever (Allergic Rhinitis)

Hay fever is a type of allergy that occurs in response to specific allergens and typically lasts for months.

Hay fever (allergic rhinitis) is a type of allergic reaction that usually causes nasal congestion, sneezing, and eye irritation. It affects 10-30% of people worldwide, including up to 7.2% of U.S. children under 17 years of age and 7.8% of U.S. adults. The medical cost of allergic rhinitis is approximately $11.2 billion, mostly due to the cost of prescription medications. These figures are probably an underestimate because many of those affected may attribute their discomfort to a chronic cold. Although childhood hay fever tends to be more common, this condition can occur at any age and usually occurs after years of repeated inhalation of allergic substances. The incidence of allergic disease has dramatically increased in the U.S. and other developed countries over recent decades.

An allergic reaction occurs when the immune system attacks a usually harmless substance, called an allergen, that gains access to the body. The immune system calls upon a protective substance called immunoglobulin E (IgE) antibodies to fight these invading allergic substances or allergens. Even though everyone has some IgE, an allergic person has an unusually large amount of IgE. This army of IgE antibodies attacks and engages the invading army of allergic substances of allergens.

Specialized cells called mast cells also participate in the allergic reaction. Mast cells release chemicals into the tissues and blood, one of which is known as histamine. These chemicals frequently cause allergic reactions because they are very irritating and cause itching, swelling, and fluid leaking from cells. Through various mechanisms, these allergic chemicals can cause muscle spasms and can lead to lung and throat tightening as seen in asthma and loss of voice (laryngitis).

Allergies occur when the body views any foreign substance or allergens as harmful and attacks it, causing reactions that range from hives, rash, sneezing, runny nose, itchy eyes, and sinus pressure.

Hay fever is a type of allergy that occurs in response to specific allergens and typically lasts for months. Symptoms are often mistaken for a cold.

Any substance can cause an allergy if exposed to an allergic person in the right way. But for all practical purposes and with few exceptions, allergic rhinitis is caused by proteins. Commonly, allergic rhinitis is a result of an allergic person coming in contact several times with protein from plants. Many trees, grasses, and weeds produce extremely small, light, dry protein particles called pollen. This pollen is spread by the wind and is inhaled. These pollen particles are usually the male sex cells of the plant and are smaller than the tip of a pin or less than 40 microns in diameter.

Even though pollen is usually invisible in the air, it is a potent stimulator of allergy. Pollen lodges in the nasal lining tissues (mucus membranes) and other parts of the respiratory tract, where it initiates the allergic response. Up to 7.8% of American adults suffer from allergic rhinitis. Approximately one in four people with allergic rhinitis also have asthma.

Since allergic rhinitis is frequently caused by pollen, symptoms occur when pollen is in the air. Trees primarily pollinate in the spring, while grasses pollinate in the spring and summer. Weeds usually pollinate in the late summer and fall. Of allergy sufferers in the United States, many are allergic to ragweed, about half are allergic to grasses, and fewer are allergic to trees. Many people are also allergic to other substances such as mold spores, animal dander protein, and dust mites, to name a few.

If you wish to know the pollen count in your area, this information can often be found in the newspaper in the weather section or you can access the National Allergy Bureau's pollen count information at their website (http://www.aaaai.org/nab/index.cfm).

Food is an uncommon cause of allergic rhinitis.

A person is genetically programmed to be allergic and is destined to be allergic from birth. People of all races and genders are affected. Symptoms commonly begin in childhood. Frequent exposure to a particular allergic substance is a risk factor for frequent attacks.

"Hay fever" is a misnomer. Hay is not the usual cause of this problem, nor does it cause fever. Early descriptions of sneezing, nasal congestion, and eye irritation while harvesting field hay promoted this popular term. Allergic rhinitis is the correct term to describe this allergic reaction, and many different substances cause the allergic symptoms noted in hay fever. Rhinitis means "inflammation of the nose" and is a derivative of rhino, meaning nose. Allergic rhinitis during a specific season is called "seasonal allergic rhinitis." When it occurs throughout the year, it is called "perennial allergic rhinitis." Rhinosinusitis is a medical term that refers to inflammation of the nasal lining as well as the lining tissues of the sinuses. This term is sometimes used because the two conditions frequently occur together.

Symptoms of allergic rhinitis, or hay fever, frequently include:

• Nasal congestion
• A runny nose with clear mucus
• Sneezing
• Nose, eye itching
• Excess tear production in the eyes

Postnasal dripping of clear mucus frequently causes a cough. Loss of the sense of smell is common, and loss of sense of taste occurs occasionally. Nosebleeds may occur if the condition is severe. Eye itching, redness, and excess tears in the eyes frequently accompany the nasal symptoms. The eye symptoms are referred to as "allergic conjunctivitis" (inflammation of the whites of the eyes). These allergic symptoms often interfere with one's quality of life and overall health.

Many people with allergies have difficulty with social and physical activities. For example, concentration is often difficult while experiencing allergic rhinitis symptoms.

Allergic rhinitis, like other allergic reactions, is not contagious. However, the symptoms of allergic rhinitis can be confused with those of a common cold, which can be spread from person to person.

Allergists are medical specialists trained in the diagnosis and treatment of allergies, including hay fever. People with hay fever also often seek care from a primary care physician, including internists, pediatricians, and family practitioners.

Allergies are usually initially diagnosed by a combination of characteristic symptoms coupled with exam findings that correspond with allergies.

If a person is experiencing typical symptoms of hay fever, a consultation with an allergy specialist can help identify the offending substances. Since the ideal way to manage an allergy is to avoid the substances that cause allergic reactions, it is important to first identify these substances (allergens). Many allergens can be suspected from information obtained in a patient's history. For example, if symptoms usually worsen with exposure to cats, then cat dander protein is a probable allergen causing the symptoms. If cutting grass is associated with the onset of symptoms, then grass allergy is probable. A patient's history of reactions is important in determining the allergies present. Allergy testing is only done when allergies are debilitating enough that patients desire allergy immunotherapy.

Because the identification of allergens is important and often difficult to pinpoint, skin testing is often needed to identify exactly the specific substance causing the allergy.

Skin testing is done with minimal discomfort and is performed as follows:

• A small amount of the suspected allergy substance is placed on the skin.
• The skin is then gently scratched through the small drop with a special sterile needle. This is known as the prick-puncture method and is typically used for initial evaluations. A second method, known as the intradermal method, involves the injection of a small amount of the test substance into the skin. Intradermal testing is more sensitive but also tends to lead to more false-positive results.
• If the skin reddens and, more importantly, swells, then an individual is said to be "sensitized" to the particular allergen. If typical symptoms occur when a sensitized individual is exposed to the suspected substance, then allergy to that substance is probable.
• The skin testing described is tolerated by the youngest of patients and should be the standard of testing.
• Skin testing is not indicated for people who are at risk of a severe (anaphylactic) allergic reaction, who have certain skin conditions, or who are taking certain medications.

Several blood tests are also available to aid in the diagnosis of allergies. These blood tests may be useful in people who cannot be skin tested due to skin diseases, who are taking medications that interfere with skin testing, or who are at a high risk of having an anaphylactic reaction to skin testing. These blood tests typically use various techniques to look for IgE antibodies in the blood and by inference suggest allergy in the tissues. If the allergy testing agrees with the history of symptoms upon exposure to the substance, then a diagnosis of allergic rhinitis is likely.

Avoidance of identified allergens is the most helpful factor in controlling allergy symptoms. Attempts to control the environment and avoidance measures often significantly aid in resolving symptoms. However, allergy avoidance is often not easy. A thorough discussion with your physician is needed, and control measures may be required daily.

If avoidance is not possible or does not relieve symptoms, additional treatment is needed. Many patients respond to medications that combat the effects of histamine, known as antihistamines. Antihistamines do not stop the formation of histamine, nor do they stop the conflict between the IgE and antigen. Therefore, antihistamines do not stop the allergic reaction but rather protect tissues from the effects of the allergic response.

The first-generation antihistamines, such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), dimenhydrinate (Dramamine), brompheniramine (Dimetapp and others), clemastine fumarate (Tavist, Allerhist), and dexbrompheniramine (Drixoral) frequently cause mouth dryness and sleepiness as side effects.

Newer, so-called "non-sedating" or second-generation antihistamines are also available. These include loratadine (Claritin), fexofenadine (Allegra), cetirizine (Zyrtec), desloratadine (Clarinex), levocitirizine (Xyzal)and azelastine (Astelin Nasal Spray). In general, this group of antihistamines is slightly more expensive, has a slower onset of action, is longer acting, and induces less sleepiness. These medications are available over the counter.

Other antihistamine side effects can occasionally occur, for example, urine retention in males, fast heart rate, and others. Always discuss the potential side effects of any medication with a physician and/or pharmacist.

Decongestants help control allergy symptoms but not their causes. Decongestants shrink the swollen membranes in the nose and make it easier to breathe. Decongestants can be taken orally or by nasal spray. Decongestant nasal sprays should not be used for more than five days without a doctor's advice, and if so, usually only when accompanied by a nasal steroid. Decongestant nasal sprays often cause a so-called "rebound effect" if taken for too long. A rebound effect is the worsening of symptoms when a drug is discontinued. This is a result of a tissue dependence on the medication.

Some people with allergies need specialized prescription medications such as corticosteroids, cromolyn, and ipratropium (Atrovent) nasal sprays. These nasal sprays do not cause the rebound effect noticed with decongestant nasal sprays. Cortisone nasal sprays are very effective in reducing the inflammation that causes swelling, sneezing, and a runny nose. Cortisone can also decrease the formation of many chemicals involved in the allergic response. Many cortisone nasal sprays are on the market through prescription only. Intranasal steroids are typically the first-line medications for patients suffering from persistent allergies. Fluticasone (Flonase) is one medication available over the counter.

Cromolyn is also an anti-inflammatory medication available over the counter. Although cromolyn is not as potent as cortisone, it is very safe. Cromolyn must be used well in advance of anticipated allergy symptoms to be useful. Ipratropium (Atrovent) nasal spray is available for drying a wet runny nose. It will not prevent allergic reactions. This is an atropine derivative and although usually very safe, a person sensitive to atropine should be cautious when taking this drug.

Montelukast (Singulair) is an inhibitor of leukotriene action, another chemical involved in the allergic reaction. This medication is used for asthma therapy and is also approved for the treatment of allergic rhinitis, but it is not a first-line therapy. It is most effective in those for whom significant congestion is a primary complaint. It may also be used in some cases together with antihistamines.

If antihistamines and nasal sprays are not effective or not tolerated by the patient, other types of therapy are available. Allergy desensitization or immunotherapy may be needed. Allergy immunotherapy stimulates the immune system with gradually increasing doses of the substances to which a person is allergic. Because the patient is being exposed to the allergy-inducing substance, an allergic reaction can occur and this treatment should be supervised by a physician. Although the exact way allergy desensitization works is not completely known, allergy injections appear to modify or stop the allergic reaction by reducing the strength of the IgE and its effect on the mast cells. This form of treatment is very effective for allergies to pollen, mites, cats, and especially stinging insects (for example, bees). Allergy immunotherapy usually requires a series of injections (allergy shots) and takes three months to one year to become effective. The required length of treatment may vary, but three to five years is a typical course. Frequent doctor's office visits are necessary.

The duration of the effect of allergy immunotherapy should last many years, if not a lifetime. Although rare, serious allergic reactions can occur while receiving allergy injections. One cannot predict who will have a severe reaction. Even after years of receiving allergy shots, a patient can experience a reaction, which is why injections are always administered in a medical setting.

Several herbal or alternative treatments have been used for symptoms of hay fever. Scientific review of the use of these preparations has been limited, although some reports suggest potential benefits for several different herbal remedies, at least in certain patients. These include the following:

• Certain Ayurvedic herbal mixes
• Butterbur (Petasites hybridus)
• Timofend (from Tinospora cordifolia)
• Cinnamon bark
• Benifuuki green tea

Many herbal formulations contain several different ingredients, each with potentially varying effects and properties. People who wish to try one of these treatments should learn about potential side effects. These kinds of products are not evaluated for safety, like over-the-counter and prescription medications. Tell your doctor about any herbal or alternative treatments you use.

Allergic rhinitis is a chronic condition, meaning that it persists over time. Some people who experience allergic rhinitis as children will notice their symptoms improve as they get older. Others may have symptoms for life. Allergic rhinitis is not associated with severe complications and can be managed effectively with medications and, in some cases, desensitization therapy.

Because allergic rhinitis is related to genetic susceptibility, prevention of the condition is not possible. However, it may be possible for some people to prevent attacks by avoiding exposure to the triggering allergic substance.