Hayfever

Welcome to our latest article on Hayfever. This condition is probably one of the most commonly experienced allergies in Australia. We will examine the body's allergy pathway to understand how current therapies work and what benefits future therapy may offer.

The term Hayfever can be considered by definition to be a seasonal problem, seasonal grass seeds, pollens and moulds around spring and early summer resulted in "fever" like symptoms and thus the term Hayfever became used to describe symptoms experienced at that time.

The scientific term for Hayfever is Allergic Rhinitis, which covers inflammation of the nasal passages and associated symptoms such as sneezing, nasal congestion, nasal itching, rhinorroea (runny nose), watery and puffy eyes.

The Allergy Process

An allergy is an exaggerated response to substances that in most people cause no problem. Hayfever commonly refers to the symptoms experienced due to an allergic reaction to a particular agent, called an allergen. The potential or capacity to become allergic to an allergen such as a grass seed or particular pollen is an inherited characteristic, 65% of people who have parents who suffer from Allergic Rhinitis will themselves have the allergy.

The body can undergo various hypersensitivity (allergic) reactions, these are classified according to types. Allergic Rhinitis is classified as a Type 1 reaction that results in an immediate allergic response following exposure to the allergen. An allergic reaction starts with a susceptible person exposed to an allergen that the body recognises as being foreign. The person's immune system produces specific antibodies to that allergen. The specific antibodies bind to mast cells and basophils that form part of the bodies defense system. The mast cells and basophils contain histamine and other inflammatory agents that cause allergy symptoms.

When exposed to the allergen again the previously produced antibodies cause mast cells and basophils to breakdown and release histamine and other inflammatory chemicals. This results in classic hayfever symptoms, nasal itchiness, congestion, sneezing, watery nose and eyes.

Allergic Rhinitis need not necessarily be seasonal and can occur throughout the year. When symptoms are perennial (all year round) the likely allergens are from the immediate environment and allergen challenges are continuous. With perennial Hayfever symptoms, environmental control measures can be most useful in reducing the severity and frequency of the allergy. Seasonal allergy sufferers are more likely to obtain benefit from drug therapy as allergens causing their symptoms tend to be out of their immediate control.

Allergy Control Measures

The management of all types of allergy is allergen avoidance, this is particularly useful in Perennial (all year round) Allergic Rhinitis. People who suffer from this condition can obtain significant improvement in their allergy symptoms and frequency by controlling their household environment. Likely household allergens are house dust mite, cockroach and animal dander.

The following control measures are useful

• Enclose bedding and pillows in airtight covers, DAC covers.
• Wash bedding in hot water, above 60 degrees centigrade
• Avoid wall-wall carpeting
• Freeze fluffy toys overnight
• Avoid upholstered fabric furniture
• Avoid fans
• Vacuum regularly with high extraction filter vacuum
• Professionally exterminate household pests regularly
• Keep surfaces clean and clear of food scraps to avoid cockroaches
• Avoid excessive moisture and humidity which promotes mould growth
• Avoid long haired pets and wash pets regularly
• Avoid irritant chemicals, strong chlorinated agents ,aerosols and strong perfumes
  

• Keep car and House windows closed
• Restrict outdoor activities such as lawn mowing, sweeping or camping
• Air-condition home using high efficiency air filter systems
• Drive air-conditioned car

Drug treatments and future therapies

The treatment of Allergic Rhinitis can be preventative or symptomatic, most treatments are available without prescription from a pharmacy, some insight into how these work will aid in understanding which agents are best for your particular symptoms.

Symptomatic drug therapies

Nasal decongestants
There are two groups within this class, oral or topical medicines. The most commonly used group being decongestant sprays such as Drixine, Otrivin, Logicin or Dimetapp. Hayfever sufferers have dilated and inflamed nasal blood vessels due to histamine release, this leads to stuffiness and increased fluid release into nasal passages. Decongestants reduce nasal stuffiness by constricting inflamed blood vessels, this reduces the local effects of histamine and gives short term symptom relief. Decongestant nasal sprays can only be used for a maximum of five days in each week otherwise blood vessels become resistant to the drugs constrictive effect and rebound congestion results.

The use of oral decongestants such as pseudo-ephedrine (Sudafed) constrict blood vessels throughout the body with the same result as decongestant sprays, they do however tend to have greater drying effects than the sprays. Oral decongestants must be avoided in people with high blood pressure as these drugs raise blood pressure.

Place in therapy
Decongestants offer limited short term symptomatic control of allergy symptoms, they act indirectly on inflammation caused by histamine release from mast cells, the advantage of these agents is their ability to achieve immediate symptom relief.

Antihistamines
Antihistamine drugs are both symptom relievers and allergy control agents. The manner in which they are taken determines how they work. Allergy symptoms are a result of the affects of histamine released from mast cells, antihistamines compete with histamine in local tissues, classic hay-fever symptoms such as nasal itching, sneezing, runny nose and watery eyes are relieved by antihistamines. Symptom relief depends on the potency of the antihistamine and how long the blocking effect of the antihistamine lasts.

Antihistamines can be divided into two classes:

• Sedation causing drugs such as Polaramine, Phenergan, and Zadine which also have secretion drying properties
• Newer, second generation antihistamines do not cause sedation to any great extent, preparations such as Claratyne, Zyrtec or Telfast are available from this class. These antihistamines do not dry nasal secretions to any great extent, some relationship between drying action and sedation seems likely.

Second Generation antihistamines can be used regularly to prevent hay-fever symptoms by blocking histamine at target cells before it is released from mast cells. This approach is more effective as the antihistamine does not have to compete with histamine before it can work. The general non-sedative properties of drugs in this class allows long term use before and during a seasonal hay-fever attack without affecting the sufferer's ability to concentrate.

See www.zyrtec.com or www.claritin.com (USA info on Loratadine = Claratin) for further information or email your OZePHARMACIST at info@Oze-Pharmacy.com.au

Topical Antihistamines (Sprays/Drops)
Antihistamines used locally were, until recently, out of favour as they could potentially cause sensitivity reactions themselves. The latest drugs available are unlikely to cause these reactions and have become popular because they work quickly to block the effects of histamine and so achieve rapid symptom relief. Topical drugs are delivered to where they need to work and in the case of allergic rhinitis are made as nasal sprays and eye drops. Levocobastine is the latest topical antihistamine drug available in Australia without a prescription, available as Livostin Nasal spray and Livostin Eye Drops these preparations are useful to treat hay-fever symptoms.

Place in therapy
Livostin is a potent, long acting histamine blocker, it is an important treatment option for hay-fever symptom relief and is not used a preventative therapy. Ask your OZePHARMACIST for further information.

Mast Cell Stabilisers (Sprays)
These drugs act by stabilising mast cells and prevent histamine release following contact with an allergen. By reducing histamine release the associated symptoms are prevented. Mast cell stabilisers are used to prevent hay-fever symptoms. Rynacrom nasal spray is available without prescription, the preparation contains sodium cromoglycate that works locally on mast cells in nasal passages to prevent allergy symptoms.

Place in therapy
Mast cell stabiliser drugs should be used on a regular basis to prevent allergy symptoms, use for symptom relief during an allergic attack is limited. The effect of these drugs in controlling mast cell histamine release will take a while to control symptoms. By using an antihistamine together with rynacrom, rapid symptom relief is achieved by the antihistamine until mast cells are stabilised and further histamine release is inhibited.

Topical Corticosteroids (Cortisone Nasal Sprays)
Corticosteroids inhibit inflammation, constrict blood vessels and block the production of histamine and other allergy mediators. When used locally to treat hay-fever symptoms they may take at least three days to achieve symptom relief. Corticosteroid nasal sprays are effective inhibitors of the allergic process and associated inflammation, they are particularly useful when used to control allergic rhinitis.

Place in therapy
Corticosteroids effectively block the allergy process associated with hayfever. These drugs do not provide immediate relief, they will effectively control seasonal and Perennial (all year round) symptoms by blocking histamine and other allergy mediator production. Go to www.beconase.com or www.nasonex.com for further information or ask your Doctor or your OZePHARMACIST.

Desensitisation Treatments
Conventional Hyposensitisation (desensitisation) therapy involves gradually administering ever increasing doses of a specific known allergen to alter an allergic response. Specialised centres that have full resuscitation facilities should only administer this form of therapy as severe allergic reactions to the treatment may potentially occur. Optimum therapy takes between three to five years, this type of treatment is long and requires some commitment. Conventional desensitisation threatment for hayfever is reserved for patients with severe and debilitating symptoms in whom other preventative treatments have failed, furthermore the duration and effort required on the part of the patient makes therapy usually unsuitable.

Latest immunotherapy options
Novel therapies are being investigated that are designed to act as vaccine like agents that alter the immune response to allergens. These vaccines are designed to either block the Immunoglobulin response which causes the allergy or activates other parts of the natural immune system to prevent a usual allergic response.

The recent windy weather along the east coast of Australia has been extreme. Nevertheless, the combination of wind and pollinating plants each year about this time, clearly signals the start of the hayfever season.

Hayfever is often thought of as a trivial condition - just a sniffle and a sneeze. In fact, for the hayfever sufferer, the impact on quality of life can be enormous, and the economic effects are significant too.

Medically speaking, hayfever is known as allergic rhinitis. Rhinitis literally means inflammation of the nasal passages; but this description is not really an adequate indication of the havoc that hayfever can cause.

The allergic inflammatory process doesn't stop at the nose. The symptoms of hayfever are many and varied. Typically they include sneezing, a clear nasal discharge, watery, itchy eyes, itchy throat, blocked nose and, not surprisingly, lack of energy. Headache sometimes occurs and the sense of smell can also be affected.

While none of these symptoms would appear to be life threatening, they can certainly have a serious adverse effect on the productivity of work or study, and destroy the enjoyment of leisure activities.

Hayfever is a global health problem. It affects about 25% of the world's population. In Australia the situation is even worse, with about 40% of adults in this country showing allergy symptoms - usually allergic rhinitis. This makes hayfever the most common chronic condition for people consulting their doctor.

Traditionally, hayfever has been classified according to when and why it occurs. It has been known as seasonal (usually related to the pollen season - beginning about now), perennial (meaning all-year round) and occupational (people working in some industries, perhaps in a bakery or on a farm, may be sensitive to the substances they breathe in at their place of employment).

A new classification describes hayfever as intermittent, where symptoms occur only now and again and persistent where the symptoms are evident for more than four weeks a year or four days a week.

Hayfever is further divided into mild or moderate to severe. In the latter case work, school or leisure activities are impaired or sleep is disturbed.

This way of describing hayfever symptoms is especially useful in Australia where the spring and summer allergy "season" can extend from August through to March and our mild weather enables the house dust mite (a likely trigger factor for hayfever) to live happily with us throughout the year.

Oral antihistamines are particularly useful for the runny nose and the sneezing. The second-generation antihistamines such as Claratyne, Telfast and Zyrtec are safe and effective, and their once-daily dosage makes them a convenient choice for the mild and intermittent symptoms of hayfever. The antihistamines Azep and Livostin nasal sprays are useful alternatives. They have a similar effect to the oral antihistamines with a faster onset of action.

For moderate to severe and persistent hayfever symptoms, the so-called intra-nasal corticosteroid sprays are the best option. They are effective against the wide range of symptoms including that so-difficult-to-treat nasal congestion. Products in this category include Aldecin, Allermax, Beconase and Rhinocort.