Inhalant allergens
Allergic rhinoconjunctivitis is caused by a reaction to inhaled allergens (i.e. travelling through the air and landing on nose/eyes/lungs).  An allergen is a tiny particle that people are often allergic to.  An inhalant allergen is a particle that travels through the air to cause allergy.  Because it travels through the air it tends to land on people's eyes or in the nose and mouth.  When this happens inhalant allergens cause the following symptoms:

• allergic rhinitis - (running, itchy nose and sneezing)
• allergic conjunctivitis - (running, itchy eyes)
• itching in the mouth, ears and palate for some people
• asthma.

Some typical inhalant allergens are house dust mite, grasses (hay fever), plantain (a weed), tree pollen and cat and dog hair.

Medical treatment
Treatment with medicine involves nasal sprays and antihistamines.  While antihistamines work quite fast, they mainly control the symptoms but do not decrease the underlying inflammation. 

Nasal corticosteroid sprays such as Flixonase or Butacort work more slowly but have a more long lasting effect.  They need to be used regularly.  Not much difference may be noticed in the first few days, but they have a cumulative effect if used daily over at least a few weeks.  They are therefore a much better preventative treatment. 

To encourage regular use it is good to have several nasal spray puffers positioned in strategic places where you know you will see them each day e.g. by your toothbrush or your desk at work.  That makes it easier to ensure regular treatment. 

Also, if you use these nasal spray puffers and your symptoms improve, it is good to continue them regularly as a preventative even once the symptoms have improved rather than waiting for symptoms to return, then trying to rescue the situation from there.

Nasal sprays must be used continuously for one month before it is possible to judge their effect.

Desensitisation

This is the most effective long term treatment.  This treatment exposes a patient to small amounts of the allergen in gradually increasing amounts.  Your immune system adjusts to this and as it does patients become gradually less allergic. 

85% of people improve with desensitisation (provided the diagnosis is correct).  The average improvement in symptoms is by 50%, with decreased medication use by 80%. 

Desensitisation involves either injections in the skin under the arm (subcutaneous desensitisation), or drops under the tongue (sublingual desensitisation). 

Injections are weekly for 14 weeks, then move to monthly for the remainder of 3 years.  It is important to continue the treatment for all of 3 years to get the maximum long lasting benefit. When the course of injections finishes, the effect usually continues for years afterwards and is permanent for many.

At present the evidence suggests that subcutaneous desensitisation is on average significantly more effective than the sublingual drops.

Cost of desensitisation and where to get this done

For patients with allergic rhinitis only, this can be done in community practice (i.e. a GP) if they are familiar with the practice.

For patients who have asthma as well, it is generally done here at our ADHB Immunology day ward, or by a private immunology specialist.

The product is not funded by Pharmac, and needs to be purchased by the patient.