Allergy Shots: are they worth the effort?
There are three basic methods to manage allergies :
- Try to avoid the allergen.
- Control the symptoms with medicines.
- Reduce the allergy or hyper-sensitivity by allergy shots or Immunotherapy.
The first is obviously the simplest and the safest method. It will work well when there is only one allergen, say for example prawn allergy. The treatment is simple – don’t eat prawns. But how does one avoid pollens ?
Taking drugs like Avil or Cetrizine helps in controlling the symptoms immediately; but for only as long as the effect of the drug lasts. They also have side effect – most notably drowsiness and sedation. They are not getting to the root of the problem.
That’s where Immunotharpay or allergy shots score. They are capable of curing the allergy, reduce the hypersensitivity, prevent development of new allergies, the benefits last even years after stopping the shots and they are not expensive either. So much for their positive attributes. The not so good points are that they have to be given repeatedly over a long period of time(usually 3 years) and do not help all patients equally. The usual experience is that about 60% patients get very good relief, 30% get some relief and 10% get very little relief with this therapy.
A vaccine is made with the specific substances the patient is allergic to. These could be pollens, house dust or fungal spores. Increasing doses are given as an injection under the skin in the upper arm, initially weekly, then fortnightly and than monthly. By doing this, the patients immune system becomes tolerant to the offending allergen. This tolerance is long lasting.
Which conditions can be helped by this:
Allergic rhinitis, allergic asthma and bite allergy.
Which conditions are generally not helped by this:
Urticaria and food allergy.
Is it safe ?
It’s not a drug. It’s a vaccine made from natural substances, but to which the patient is allergic. Local reactions in the form of itching and minor pain at the injection site are common. They are not troublesome, do not require medication and in fact reassure the patient and the doctor that the vaccine is working. Very rarely systemic reactions soon after the vaccine can occur. This would cause increasing symptoms of the basic disease like sneezing or wheezing. Blood pressure could drop. Fortunately, these are very rare. It is for this reason that the patient has to wait in the doctors clinic for 10-15 minutes after the shot.
How long is the course?
It is usually for 3 years. After that it could be stopped. A majority of the patients continue with the benefits even after stopping the injections. In some patients the symptoms start coming back. In these patients the vaccine is continued for longer periods on a monthly basis.
Which type of patients get the maximum benefit from Immunotherapy ?
- Younger patients.
- Allergic rhinitis patients.
- Milder asthmatics.
- Clearly seasonal allergies.
- Lesser number of allergens.