COMMENTARY
FOOD
ALLERGY
By Walter R. Kessler, M.D., Ph.D.
Department of Pediatrics, College of Physicians arid Surgeons, Columbia University, the Babies Hospital, and the Institute of Allergy, Roosevelt Hospital, New York City
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VOLUME 21 APRIL 1958 NUMBER
4
A
VARIETYof
disorders
and
symptom
complexes have been ascribed to
al-lergy-often to hypersensitivity to foods. In
the majority of instances, however, it has
not been possible to produce objective
evi-dence for the existence of an
antigen-anti-body reaction and such a mechanism has
been assumed rather than demonstrated.
Instances of true food allergy occur. Their
frequency however is difficult to determine
with any degree of accuracy. Dr. Pratt (PEDIvrrucs, 26:642, 1958) has properly
called attention to the inadequate evidence on which practitioners as well as laymen
frequently ascribe signs and symptoms to
allergy to foods.
Even when the diagnosis is based on
good clinical observation, it may not be
possible to demonstrate an immunologic
mechanism. This difficulty is true not only
with respect to allergic reaction to foods
but with the large group of drug reactions
as well. In the latter cases, it is often
pos-sible to demonstrate repeatedly a character-istic untoward response and yet, in most
in-stances, no specific antigen-antibody
reac-tion can be proven. The clinical problem
with respect to drugs is considerably
sim-pler than that existing for foods, since the
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drug
can
be
administered under well con-trolled circumstances and does not form a part of the usual dietaryintake.
Objective
evidence
such as skin tests
may
be helpful in the diagnosis of food allergy(and will be discussed later). Changes in
blood pressure or leukocyte count have not been sufficiently consistent to
be clinically
useful. A high eosinophil count in theperipheral blood or in
the
stool, as well asroentgenographic changes in the gastroin-testinal tract following the ingestion of the
offending food, cannot be used in support
of an immunologic mechanism. Black’s
leukocyte-survival time as an indicator for
sensitization is of considerable interest, but
has not yet received adequate study and
confirmation by other workers.
Dr. Pratt’s stimulating article therefore
presents a viewpoint which has long needed
such clear exposition. Before one can
pos-tulate food allergy to be the basis for the
patient’s disorder, such factors as parental
attitudes and a variety of other psychologic
factors must be taken into consideration. The distinction of food intolerance has been
emphasized by Dr. Pratt. Since this is mere-ly another way of stating that the patient
reacts in an unusual manner to what
524
FOOD
ALLERGY
dinarily is a well-tolerated and benign
sub-stance without indicating the nature of this
reaction, it does not aid in clarification of
the problem; per se it must not be used
as an indicator of hypersensitivity to food.
To the practicing pediatrician, constantly
confronted by infants and children whose
parents consider their behavior as being
outside the realm of normal, and where the
diagnosis of “allergy to some food” has
al-ready been made by the parent prior to
consultation with their physician, Dr. Pratt’s article should “give food for thought.” As he points out, “the physician should respect the promotion of good
eat-ing habits and . . . while he should readily
respect foods as a causal symptom, he will
accept this situation only after carefully
de-signed studies Good eating habits and
a wholesome attitude towards food in chil-dren largely reflect parental attitudes, their own freedom from anxieties and doubts. If
eating is made a pleasurable experience without the proverbial “it is good for you,”
or “he will only eat it for me if I feed him,”
the number of feeding problems will be
sig-nificantly reduced. It should not become
necessary for the child to “steal” foods that
are prohibited in order to satisfy his crav-ings. If a causal relationship exists between the ingestion of a given food and the de-velopment of symptoms, it is not unusual
to obtain full co-operation even from the
very young patient. The mother may,
es-pecially if the problem has not been dis-cussed with her in sufficient detail, feed a
forbidden food because she feels her child’s
health will suffer if it is withheld. This arouses a great deal of anxiety and feelings
of guilt and further complicates the clinical
problem.
Consideration of the possibility of allergy
to food as the causative factor in the
pro-duction of the patient’s symptoms must
nec-essarily be based on a complete and thor-ough history. There is nothing in the physi-cal examination which will aid in
establish-immediate, occurring within a few minutes
after the ingestion of the offending food;
the second, in which the reaction may be
delayed for from one to several hours. It is in the second group that the correlation
between the ingestion of the specific food
and the production of clinical symptoms is
often made only with considerable
diffi-culty.
In the first group, there is usually prompt
and vigorous vomiting which may be
asso-ciated with diarrhea, urticaria, angioedema,
laryngeal edema with respiratory distress, asthma or vasomotor collapse. These reac-tions are often dramatic and frightening,
and it is not unusual for the parent to
con-front the physician with the diagnosis.
Since these reactions often occur within a
few minutes after ingestion of the food,
there must be sufficient absorption of
un-altered native protein, through the intact
mucous membrane of the oropharynx and
upper segments of the gastrointestinal
tract, to produce signs and symptoms. In this acutely-reacting group, skin tests of the immediate-wheal and flare type are often obtained with the commonly used aqueous protein extracts of the offending food.
In-deed the reaction produced by intradermal inoculation of even a minute amount of the test material may be associated with
se-vere constitutional symptoms. When con-firmatory evidence is sought in these cases, skin tests should be done by the passive-transfer method. This procedure eliminates any severe or dangerous reaction on the part of the patient and can be repeated at will. The acuity with which the child is able to recognize the offending food may be
startling. The patient will often refuse the
offending agent even when disguised or
in-corporated in a mixture. It should be
pointed out that though such cases occur, they do not materially aid in our under-standing of the problem of the patients who show reactions of the delayed type. In
objective evidence for, allergy as the under-lying mechanism. Confirmation for this thesis must nevertheless be based on
clini-cal trial of feeding the offending food with the production of characteristic symptoms. As noted, these reactions may be dramatic,
unacceptable to the parent, and therefore not readily repeated.
Before going on to a discussion of the
delayed type of food sensitivity, some clari-fication of the importance of skin tests using food antigens should be presented. This problem has been discussed in the litera-ture at great length and obviously without
general agreement. The usual food aller-gens for diagnostic testing are prepared
by alkaline, aqueous extraction of the
pro-tein constituents. Their stability varies, is
often poor, so that after a brief period of
time the active principle deteriorates. It is
conceivable that these extracts do not
repre-sent the actual antigens taking part in the allergic reactions; this may be especially true of reactions of the delayed type.
Ordinarily, the reactions are not as
se-vere or dramatic as in the acutely-reacting group. Recently, two infants were observed at the Babies Hospital in New York who
had episodes of profuse vomiting, diar-rhea with occult blood in the stool and
vasomotor collapse but no urticaria, angio-edema or asthma. These occurred about 90 minutes after ingestion of the offending food (squash in one case, sweet potato in
the other). By deliberate feeding in the
hospital, it was possible to demonstrate this
specific intolerance in the infant who was
sensitive to sweet potato. A more detailed presentation of these cases will be made
in a separate publication. It is of interest that in neither instance was a positive skin
test obtained with the offending food al-lergen by the passive-transfer method.
For the practicing clinician, careful ob-servations and complete records of all foods ingested at each meal along with
simul-taneous recordings of changes in the child’s behavior and symptoms, may offer a prac-tical procedure. Further observations will then be necessary to obtain a close
rela-tionship between feeding and withholding
of the offending food or foods. When this
is done repeatedly, then food allergy may
be suspected. In order to prove its
exist-ence, objective experimental methods,
which are now sorely needed, must be
utilized to confirm the finding.
As pediatricians, we are dealing with
growing, maturing individuals whose
hab-its, attitudes and behavior are in the process
of formation. This facet of the problem
must receive the attention and thought
which it deserves. To use food allergy as a “scrap-basket diagnosis” for a variety of problems, for which no other diagnoses
have been found, is unsound and fails to
add to our understanding of an important
pediatric problem.
Tmi SURGERY OF PREMATURE INFANTS, P. P. Rickham. (Arch. Dis. Childhood, 32:508,
December, 1957.)
This paper is a general discussion of the surgical conditions encountered in 122
premature infants in the author’s experience, during a 4-year period, and of the
problems presented in their management. Topics discussed include anaesthesia, pre-vention and treatment of infection, control of body temperature, supportive therapy
