Immunotherapy
Patients with food or episodic allergies are usually prescribed antihistamines
as these drugs counteract the effects of histamine, one of the major chemicals
released in an allergic reaction. If sufficient antihistamine is given early
enough, most allergic reactions will resolve.
Patients with allergy to unavoidable allergens, such as house dust mite and
pollens will commonly find themselves needing repeated doses of
antihistamines and may find that even with regular antihistamines, their
symptoms break through. For these inhaled allergens (aeroallergens), regular
preventative doses of antihistamines as well as local therapy with inhaled
steroids and antihistamine eye-drops might be prescribed.
If despite all of this treatment, the allergic disease persists and causes
unpleasant symptoms, then an immunomodulatory strategy might be used.
The immunomodulatory strategy targets the immune response itself and aims
to redirect it away from allergy and back toward a more healthy / normal
immune response. For most pollens and foods, this normal immunity would
be to ignore the allergen. To achieve this, we give small doses of the allergen
in a form to help the immune system to respond differently. At the moment,
this is a field of science that is developing quickly and improvements are
occurring all the time.
At the present time, we are using these immunomodulatory strategies (also
called immunotherapy or desensitisation) to treat allergy to grass and tree
pollens principally.