ALLERGY TESTING BY SERIAL DILUTION TESTING
A Fast and
Effective Way to Control Allergies
Before
discussing the Serial Dilution Testing, let us first review
the common traditional skin allergy testing and see why such
testing does not provide an optimum solution in most
instances. There are 3 most common traditional skin testing
methods used to diagnose inhalant allergies:
- Scratch Test: Here
the most superficial part of the skin is scratched
and a strong extract is applied to the skin. If you
are sensitive to it, it may show a positive
reaction. There are a few problems with this test:
- This test is not
as sensitive and as informative as we would like
it to be. This is because the superficial part
of the skin is very insensitive. This means that
to elicit a positive response from the skin, we
have to use a strong concentration of the
extract. Therefore, both false negative and
false positive tests are likely - false negative
because of relative insensitivity of the skin
and false positive because of some irritant
effect of the strong concentration.
- When the test is
positive, it is very difficult to quantify
precise sensitivity because a definitely
positive test may not differ much from a
moderately positive test. Therefore, when the
allergist starts a patient on an allergy
injection build-up, his goal is to start at a
dilution that is far below than what could
possibly cause a reaction in the patient. This
means that the physician may start treatment at
a dilution 1:100,000, 1:1,000,000 or even at a
weaker level. Suppose your treatment dose is at
a dilution that is 1:50 and if you are started
at a dilution 1:1,000,000, you can very well see
how it may take 2 to 3 years to reach the
maintenance dose.
- A third problem
is that after the testing is completed, all
allergens are put in equal dilutions since there
is no way to know the precise relative
sensitivity. Therefore, even when time is given
to build up to the proper dosage for certain
antigens, one may start reacting to some of the
ingredients (allergens) while for others, the
dose may still be low. In other words, for some
allergens the dose may be right, while for
others it may be too little or too much, causing
reactions.
- In the interim
period (which may be 2-3 years) before the
patient has a chance to reach the maintenance
dose, he has to depend upon drugs to control the
symptoms.
- Prick Test: Here a
drop of strong extract is applied to the skin and
then superficial layer of the skin is pricked
through the drop.
The Scratch and Prick Test are about the same as far
as the sensitivity is concerned. Therefore, they
have similar limitations.
- Intradermal Test:
Here, a small amount of the allergy extract is
injected into the skin and a small wheal is made
which looks like a small mosquito bite. The deeper
layer of the skin is far more sensitive than the
most superficial layer. Therefore, intradermal tests
become far more sensitive than the superficial tests
- Scratch and Prick Tests. Moreover, because of the
sensitivity of the test, you cannot test with strong
extracts as you do with the other two tests.
Therefore, a much weaker dilution is needed to do
the skin testing to avoid the reaction. However, if
your level of sensitivity is lower than the dilution
at which the test is being performed, it will give a
falsely negative test. Moreover, the intradermal
test does not give us a relative level of
sensitivity since a definitely positive test may not
differ much from a moderately positive test. So
intradermal testing with a single dilution is also
of limited value.
Now, let us
discuss Serial Dilution Testing. This is a modification of
intradermal testing. In the typical intradermal testing, as
mentioned above, only one dilution is tested. So, if you
test with a dilution that is lower than the patient's level
of sensitivity, the test is likely to show negative and if
you test with a dilution that is far above the patient's
actual level of sensitivity, it may cause a reaction. To
overcome this objection, Dr. Herbert J. Rinkel modified the
intradermal test. This modified testing is called "Serial
Dilution Testing". He made various dilutions of an extract
and started testing intradermally, from the weaker to the
stronger dilutions. In doing so, he discovered the most
sensitive, fast, and economical way of testing and treating
inhalant allergies. He found that when you test with a
dilution that is below the patient's level of sensitivity,
the skin will give a negative test and if you test with
progressively stronger and stronger dilutions, and if the
patient is sensitive to that allergen, it will show a
positive wheal on a dilution that corresponds with the
patient's level of sensitivity. See Illustration # 1 that
shows how various dilutions are made.
These dilutions are made in a 1:5 dilution factor.
Therefore, bottle #9 (dilution #9) is the weakest and bottle
# 1 (dilution #1) is the strongest dilution. From this
testing, we can find the relative sensitivity of each
allergen and then we can start treating at the same dilution
as the skin is showing a positive wheal. For most allergens,
the treatment dose will be found within the same dilution.
Therefore, one can actually reach the maintenance dose
within 4-5 injections, i.e. 4-5 weeks, instead of taking 2-3
years to reach the maintenance dose. After you are done with
the testing, you do not need to start at a very low level,
like 1:1,000,000, then go to 1:100,000, then 1:10,000, and
then 1:1,000, etc. If you are reacting at 1:100 dilution, or
1:500 dilution, we can start the treatment at those levels.
By testing this way, we overcome all of the objections that
pertain to scratch and prick tests. We find this test to be
a very quick and effective way to control inhalant allergies
because the sooner you reach the maintenance dose, the
faster the relief. This means feeling better, controlling
symptoms, and getting off drugs such as antihistamines,
decongestants, wheezing, cough medications, etc.
This is what the allergy testing sheet looks like. The top
numbers 1 through 9 show various dilutions of the extract
and X shows where the patient's skin test became positive.
From this example you can see that this patient is reacting
to dilution #2 on house dust, dilution #3 on house dust
mite, dilution #5 on dog, and dilution #4 on cat. Now we
know the precise relative sensitivity of each allergen and
we will start treating them on these levels. This will
provide highly individualized doses for each allergen,
making it the quickest way to reach the maintenance dose and
bringing relief to patient's symptoms and quickly reduce the
need for drugs.
In this
illustration, the patient was tested on dilution #4 and #3,
to which the test was negative and then the patient was
tested with dilution #2, where the test became positive and
on dilution #1, it became more positive. This means that the
patient will be started on the treatment program at dilution
#2, which is 1:250 dilution; instead of starting at
1:1,000,000 and building and building weekly to reach this
dilution.
In a patient
with just inhalant allergies (i.e. - those patients that do
not have concomitant food or chemical sensitivities) a
typical course of events is as follows:
- 1st injection may
provide 1-2 days of relief.
- 2nd injection may
provide 2-3 days of relief.
- 3rd injection may
provide 3-4 days of relief.
- 4th injection may
provide 4-5 days of relief.
- 5th injection
usually provides 5-7 days of relief.
A dose that
gives 5-7 days relief is the maintenance dose. When you
reach the maintenance dose, it provides the following
benefits:
i. It relieves
the patient's symptoms, such as runny nose, sneezing,
coughing, wheezing, difficulty in breathing, itching of
nose, itching of eyes, watering of eyes, etc.
ii. It reduces
the need for medicines, often tremendously, such as the need
for antihistamines, nasal sprays, wheezing medicines,
bronchial sprays and other symptomatic therapy.
CO-SEASONAL
TREATMENT:
If you have hay
fever, you know what it means -- in the pollen season any
time spring through fall, you feel miserable with sneezing,
running nose, watering eyes, coughing, wheezing, and
itching. While most people are enjoying the outdoors, you
are trying to find refuge indoors. Depending upon your
pollen season, you may be miserable for 1-6 months out of
the year. Co-seasonal treatment means that when you come for
the testing, you are already reacting to pollens and are
having symptoms. We test and treat the patient in the same
season and provide relief in the same season. In such a
situation, the time can be cut even further to only 2 weeks.
OTHER
APPLICATIONS OF SERIAL DILUTION TESTING:
We have thus far
discussed serial dilution testing in relation to inhalants
only. The same technique can be applied to all other
allergies, including foods and chemicals.
1.
Desensitization for foods:
Serial dilution
testing establishes a treatment dose for foods called
neutralization dose. Once the testing is completed, the
precise treatment dose has already been determined. This
treatment dose is called the neutralization dose. This does
not require any build-up. Therefore when you take your first
dose, say a day after the testing, you have already reached
the treatment of maintenance dose right there and then.
Desensitization for foods allows you to eat the foods you
are sensitive to in small to moderate quantities which would
otherwise make you quite sick. For example, if you are
allergic to common foods such as milk, egg, wheat, corn,
sugar, yeast, and soy bean, it is really hard to avoid them.
2.
Desensitization for chemicals:
Similarly, the
neutralization dose or a treatment dose can be established
for common chemicals in our environment that make a patient
sick and which are hard to avoid, such as perfumes, tobacco
smoke, formaldehyde, cosmetics, auto exhaust, gasoline,
cleaning products, etc. This allows the patient to visit
places where the patient may be getting sick, such as
shopping centers and malls, restaurants, place of work,
school, etc.
