Testing For Allergies 227Problems
When it works, the method works very well. A number of difficulties
may occur, however. About 10 per cent of cases are plagued with shifting
end-points. Repeat testing becomes necessary and this is troublesome and
may be expensive. These shifts can occur very rapidly. So that by the time
the patient is supplied with his or her prescription, it is ineffective. In these
cases, even retesting won’t help. However, this only applies to less than 5
per cent of those tested.
Unfortunately, the people who need this kind of treatment most,
the very sick, ‘unstable’ patients, are the ones most likely to be troubled by
this shifting end-point phenomenon.
Even if the antidotes are not effective, however, the method is still
good for diagnosis. It can pinpoint rapidly the worst allergens for a patient.
This will help reduce his or her body load. The method is also very safe.
Reactions are common but rarely severe, and in any event can be relieved
rapidly by the corresponding neutralizing dose.
Sublingual Provocation
A modification of the Lee-Miller technique is to do the testing
sublingually. This dispenses with syringes and the need for a physician
altogether. A food or other concentrate is placed under the tongue and the
reactions noted. If the patient experiences a symptom, this is neutralized,
as before, by serial dilutions. The dilution that switches off the symptom
completely is taken as the end-point (Dickey, LD Sublingual Use of
Allergenic Extracts (monograph) ed. H C King, Elsevier, New York, 1981).
There is no essential difference between this approach and using an
injection, although naturally there are fewer parameters by which to judge
reactions or the lack of them. Instead of being able to view a wheal, its size
and characteristic, the clinician has only the patient’s subjective symptoms
to rely upon, plus what he or she can observe objectively.
Yet with practice it is possible to become quite adept at spotting
subtle shifts in the patient’s mood or attitude, skin colour, etc. The
neutralizing dose would be that which leads the patient to declare his
or her symptoms ‘switched off ’ and the clinician to note that whatever
manifestations arose have disappeared again.