An allergic reaction affecting the eyes and nasal passages, resulting in watering of the eyes, nasal congestion, and sneezing. It is usually provoked by exposure to the pollen of grasses in the air, which are present in highest concentrations in late spring or early summer, but the reaction is not confined to any season or to a single stimulus. Other allergens are house dust, spores of fungi, and dander from animals. Symptoms can be reduced by antihistamine drugs.
Hay feverClassifications and external resources
| Pollen grains from a variety of common plants can cause hay fever. | |
| ICD-10 | J30.1 |
| ICD-9 | 477 |
Seasonal allergic rhinitis, also called pollinosis, hay fever or nasal allergies, and often also written together as hayfever, is a collection of symptoms, predominantly in the nose and eyes, that occur after exposure to airborne particles of dust, dander, or the pollens of specific seasonal plants in people who are allergic to these substances.
When these symptoms are caused by pollens, the allergic rhinitis is commonly known as "hay fever", after the fact it is most prevalent during haying season.
Causes
Allergies are caused by an oversensitive immune system, leading to a misdirected immune response. Allergy occurs when the immune system reacts to substances (allergens) that are generally harmless and in most people do not cause an immune response.
As noted above, hay fever involves an allergic reaction to pollen. A virtually identical reaction occurs with allergy to mold, animal dander, dust, and similar inhaled allergens.
The pollens that cause hay fever vary from person to person and from region to region; In northern latitudes birch is considered to be the most important allergenic tree pollen, with an estimated 15-20% of hay fever sufferers sensitive to birch pollen grains. An estimated 90% of hay fever sufferers are allergic to grass pollen. Weeds:ragweed (Ambrosia), plantain (Plantago), nettle/parietaria (Urticaceae), mugwort (Artemisia), Fat hen (Chenopodium) and sorrel/dock (Rumex)
In addition to individual sensitivity and geographic differences in local plant populations, the amount of pollen in the air can be a factor in whether hay fever symptoms develop.
The time of year at which hay fever symptoms manifest themselves varies greatly depending on the types of pollen to which an allergic reaction is produced. As most pollens are produced at fixed periods in the year, a long-term hay fever sufferer may also be able to anticipate when the symptoms are most likely to begin and end, although this may be complicated by an allergy to dust particles.
When an allergen such as pollen or dust is inhaled by a person with a sensitized immune system, it triggers antibody production.
Some disorders may be associated with allergies.
Allergies are common.
Symptoms
The effect of hayfever can vary greatly: some people may only be mildly afflicted, whereas others may suffer greatly. runny nose (and occasionally nosebleeds) impaired smell (and thus sensitivity to flavours) sneezing stuffy nose (nasal congestion) watering eyes sore throat wheezing fever cross-reactivity allergy to some fruits conjunctivitis
Signs and tests
The history of the person's symptoms is important in diagnosing allergic rhinitis, including whether the symptoms vary according to time of day or the season;
Allergy testing may reveal the specific allergens the person is reacting to. Skin testing is the most common method of allergy testing. Less commonly, the suspected allergen is dissolved and dropped onto the lower eyelid as a means of testing for allergies. (This test should only be done by a physician, never the patient, since it can be harmful if done improperly.)
In some individuals who cannot undergo skin testing (as determined by the doctor), the RAST blood test may be helpful in determining specific allergen sensitivity. For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes.
Prevention
Avoiding exposure to pollen is the best way to decrease allergic symptoms.Healthlink
Remain indoors in the morning and evening when outdoor pollen levels are highest. A small amount of vaseline around the eyes and nostrils will stop some pollen from entering the areas that cause a reaction A very small amount of Vicks VapoRub(TM)cream around the eyes will effectively reduce the itching (however: vapors will cause a cold sensation and watery eyes)Also:
It may be helpful to humidify the room you are in to help clean the allergens out of the air, perhaps by using a humidifier, leaving a bowl of water around or leaving a wet towel in the room.Treatment
The goal of treatment is to reduce allergy symptoms caused by the inflammation of affected tissues. The best "treatment" is to avoid what causes your allergic symptoms in the first place.
Medication
The most appropriate medication depends on the type and severity of symptoms. Specific illnesses that are caused by allergies (such as asthma and eczema) may require other treatments.
Options include the following:
Fast-acting strong antihistamines such as drugs including chlorphenamine which relieve the symptoms after a hayfever "attack" Short-acting antihistamines, which are generally over-the-counter (non-prescription), often relieve mild to moderate symptoms, but can cause drowsiness. New leukotriene receptor antagonists, such as montelukast (Singulair) and zafirlukast (Accolate) have proven very effective in dealing with allergic rhinitis, without the common side-effects of the first-generation antihistimines, such as drowsiness. "Allergy shots" (Hyposensibilization, immunotherapy) are occasionally recommended if the allergen cannot be avoided and if symptoms are hard to control.Expectations
Most symptoms of allergic rhinitis can be readily treated.
In some cases (particularly in children), people may outgrow an allergy as the immune system becomes less sensitive to the allergen. However, as a general rule, once a substance causes allergies for an individual, it can continue to affect the person over the long term.
More severe cases of allergic rhinitis require immunotherapy (allergy shots) or removal of tissue in the nose (e.g., nasal polyps) or sinuses.
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