Hay fever and Allergies

Allergic rhinitis, known as hay fever, is caused by pollens of specific seasonal plants, airborne chemicals and dust particles in people who are allergic to these substances. It is characterised by sneezing, runny nose and itching eyes. This seasonal allergic rhinitis is commonly known as 'hay fever', because it is prevalent during the hay making season. It is particularly prevalent from late May to the end of June. However it is possible to suffer from hay fever throughout the year. The symptoms of a 'cold' of long duration should be suspected of being allergic rhinitis.

As noted above, hay fever involves an allergic reaction to pollen. A similar reaction occurs with allergy to mold, animal dander, dust and similar inhaled allergens. Particulate matter in polluted air and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate the condition.

The pollens that cause hay fever vary from person to person and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated plants are the predominant cause. Pollens of insect-pollinated plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include:

Trees: such as birch (Betula), alder (Alnus), hazel (Corylus), hornbeam (Carpinus), horse chestnut (Aesculus), willow (Salix), poplar (Populus), plane (Platanus), linden/lime (Tilia) and olive (Olea). 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. Olive pollen is most predominant in Mediterranean regions.
Grasses (Family Poaceae): especially ryegrass (Lolium sp.) and timothy (Phleum pratense). 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. Hot, dry, windy days are more likely to have increased amounts of pollen in the air than cool, damp, rainy days when most pollen is washed to the ground.

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. The pollen count, in general, is highest from mid-spring to early summer. 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. These antibodies mostly bind to mast cells, which contain histamine. When the mast cells are stimulated by pollen and dust, histamine (and other chemicals) are released. This causes itching, swelling, and mucus production. Symptoms vary in severity from person to person. Very sensitive individuals can experience hives or other rashes.

Some disorders may be associated with allergies. These include eczema and asthma.

Allergies are common. Heredity and environmental exposures may contribute to a predisposition to allergies. It is roughly estimated that one in three people have an active allergy at any given time and at least three in four people develop an allergic reaction at least once in their lives.

The two categories of allergic rhinitis include:

seasonal - occurs particularly during pollen seasons. Seasonal allergic rhinitis does not usually develop until after 6 years of age.
perennial - occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.

Prevention
Avoiding exposure to pollen is the best way to decrease allergic symptoms.

  • Remain indoors in the morning and evening when outdoor pollen levels are highest.
  • Wear face masks designed to filter out pollen if you must be outdoors.
  • Keep windows closed and use the air conditioner if possible in the house and car.
  • Do not dry clothes outdoors particularly sheets and pillow cases.
  • Avoid unnecessary exposure to other environmental irritants such as insect sprays, tobacco smoke, air pollution, and fresh tar or paint.
  • Avoid mowing the grass or doing other yard work, if possible. Avoid fields and large areas of grassland.
  • Regular hand- and face-washing removes pollen from areas where it is likely to enter the nose.
  • A small amount of petroleum jelly around the eyes and nostrils will stop some pollen from entering the areas that cause a reaction
  • Avoid bicycling or walking - instead use a method of confined transportation such as a car.
  • Wear sunglasses, which reduce the amount of pollen entering the eyes.
  • Take a shower before going to bed and change bed linen often to avoid extra exposure during the night

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:

Systemic therapy
Therapies that have an overall effect on a person's body and therefore thay may help for all of the symptoms include:

Antihistamines
these are taken by mouth and may relieve mild to moderate symptoms. The first-generation (non-selective or classical) antihistamines such as chlorphenamine (Piriton tablets) and promethazine are perhaps the most effective, but their sedative side effects limits their usefulness compared to the newer second-generation and third-generation (selective, non-sedating) antihistamines such as loratadine (Clarityn) and cetirizine (Zirtek). Cetirizine is our recommendation at totalpharmacy. It is taken once-a-day, is non drowsy and can be purchased in 30 day packs for under £5. Contains the same active ingredient as the brand name Zirtek and will treat the majority of hay-fever symptoms.

Topical therapy
Localised treatments may give more effective relief of eye or nasal symptoms.


Nasal treatments
Steroid nasal sprays are effective and safe, and may be effective without oral antihistamines. These medications include, beclomethasone (Beconase), used twice daily which is also available as a less expensive unbranded version and fluticasone (Flixonase) which is used once daily. They take several days to act and also need be taken continually through the allergic season as their therapeutic effect is preventative rather than symptomatic.
Cromoglicate is a drug that stabilizes mast cells and prevents their degranulation and subsequent release of histamine. It is available as a nasal spray for treating hay fever, although generally less effective than the nasal steroid sprays.
Antihistamine
Azelastine is the only antihistamine available as a nasal spray.
Topical decongestants
may also be helpful in reducing symptoms such as nasal congestion, but should not be used for long periods (more than 1 week) as stopping them after protracted use can lead to a rebound nasal congestion (Rhinitis medicamentosa).

Eye treatments: (generally only last for 28 days once opened)
Cromoglicate is used as eye drops (Opticrom, Optrex Allergy). Like steroid nasal sprays the eye drops take a few days to build up an effect and requires continuous use through the allergy season. Otrivine-Antistin is an antihistamine drops which can be used as and when necessary.


Honey
Eating locally produced unfiltered honey is believed by many to be a treatment for hayfever, supposedly by introducing manageable amounts of pollen to the body. Clinical studies have not provided any evidence for this belief.


Expectations
Most symptoms of allergic rhinitis can be readily treated. If you have tried a product and it has not treated all of your symptoms, contact us for further advice.

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 referral to your general practitioner.

Complications
drowsiness and other side effects of antihistamines
side-effects of other medications (see the specific medication)
asthma
sinusitis
nasal polyps
disruption of lifestyle (can be extensive)

For much more information click Hay-fever or go to NHSDirect at www.nhs.u

This page was last updated: Monday 25 September, 2017