Immunotherapy Safety for the Primary Care ... - U.S. Coast Guard

J ALLERGY CLIN IMMUNOL
VOLUME 120, NUMBER 3
Cox et al S49
no data to support allergen immunotherapy as a treatment
for non–IgE-mediated symptoms of rhinitis or asthma. As
is the case in interpreting positive immediate hypersensitivity
skin test results, there must be a clinical correlation
with the demonstration of in vitro allergen-specific IgE
levels and clinical history of an allergic disease.
There is no evidence to support the administration of
immunotherapy based solely on results of specific in vitro
testing, as is being done by both commercial laboratories
and some physician’s offices. This is promoting the remote
practice of allergy, which is not recommended.
Clinical correlation. Summary Statement 25: The
allergen immunotherapy extract should contain only clinically
relevant allergens. A
The omission of clinically relevant allergens from an
allergic patient’s allergen immunotherapy extract contributes
to decreased effectiveness of allergen immunotherapy.
The inclusion of all allergens to which IgE antibodies
are present, without establishing the possible clinical
relevance of these allergens, might dilute the content of
other allergens in the allergen immunotherapy extract and
can make allergen immunotherapy less effective.
Knowledge of the total allergenic burden facing a
patient and the realistic possibility of avoidance is important
in determining whether allergen immunotherapy
should be initiated. A patient’s lifestyle can produce
exposure to a wide variety of aeroallergens from different
regions, necessitating inclusion in the extract of multiple
allergens from different geographic areas. Many individuals
travel extensively for business or pleasure into
different regions, and symptoms might worsen at these
times. However, inclusion of allergens to which IgE
antibodies are present but that are not clinically relevant
might dilute the essential allergen components of the
allergen immunotherapy extract so that immunotherapy
might be less effective. Determination of the significance
of indoor allergens for a particular patient is harder
because it is difficult to determine exposure in the home,
school, and/or workplace. Historical factors, such as the
presence of a furry animal in the home, a history of water
damage and subsequent fungal exposure, or a history of
insect infestation, might be helpful. However, such information
is subjective and is often of uncertain reliability.
In addition, some studies have demonstrated significant
indoor levels of cat and dog allergen in households
without pets 228 and significant levels of mouse allergen
in suburban 229 and inner-city 230 homes of asthmatic children.
In the National Cooperative Inner-City Asthma
Study, 33% of the homes had detectable rat allergen
(Rat n 1), and a correlation between rat allergen sensitization
with increased asthma morbidity in inner-city children
was found. 231 Fur-bearing pets and the soles of
shoes are also conduits by which molds and other ‘‘outdoor’’
allergens can enter the home.
Several commercial immunoassays to measure the
presence of indoor allergens (eg, dust mite, cat, cockroach,
and dog) in settled house dust samples are available and
might provide useful estimates of indoor allergen exposure.
Nevertheless, for most patients, determination of the
clinical relevance of an allergen requires a strong correlation
between the patient’s history and evidence of
allergen-specific IgE antibodies.
Skin tests and in vitro IgE antibody tests. Summary
Statement 26: Skin testing has been the primary diagnostic
tool in clinical studies of allergen immunotherapy.
Therefore in most patients, skin testing should be used
to determine whether the patient has specific IgE antibodies.
Appropriately interpreted in vitro tests for specific
IgE antibodies can also be used. A
The use of standardized allergens has greatly increased
the consistency of skin test results for these antigens.
Controlled studies in which the clinical history has
correlated with the skin test results have demonstrated
the efficacy of immunotherapy for relevant allergens.
25,26,112,130,134,135,140,141,149,154 Skin testing can
also provide the physician with useful information about
the appropriate starting dose of selected allergens. On
rare occasions, systemic reactions can occur from skin
testing in a highly sensitive individual. 232,233 In addition,
skin tests might be difficult to perform in patients with
dermatographism or atopic dermatitis. In vitro tests are
particularly useful in such patients.
Studies indicate that skin testing is generally more
sensitive than in vitro tests in detecting allergen-specific
IgE. 234,235 Based on inhalation challenge test results,
skin tests have shown specificity and sensitivity generally
superior to those of in vitro tests. The comparability of
skin tests and in vitro tests for specific IgE antibodies depends
on the allergen being tested. For all of these reasons,
skin testing is preferable as a method for selection of allergens
for inclusion in immunotherapy and determining the
starting dose for an immunotherapy program. Among
the skin testing techniques available, a properly applied
percutaneous (prick/puncture) test consistently produces
reproducible results. Generally, prick testing is sensitive
enough to detect clinically relevant IgE antibodies when
potent extracts, such as grass 236 and cat, 237 are used.
Intradermal/intracutaneous skin testing might be required
for some allergen extracts. It is appropriate in some patients
to use in vitro tests for specific IgE antibody as an
alternative to skin tests in the diagnosis of allergic rhinitis,
allergic rhinoconjunctivitis, allergic asthma, and stinging
insect hypersensitivity. In vitro tests can also be used to
define the allergens that should be used in allergen immunotherapy.
If the allergy skin test result is negative and the
in vitro test result is positive, a controlled challenge can be
performed, and if the latter is positive, immunotherapy can
be considered. In the case of Hymenoptera venom, immunotherapy
can be started even without a live sting challenge
in patients with negative skin test results and
positive in vitro test results. However, there are no published
results of the effectiveness of Hymenoptera VIT
in patients with negative skin test results and positive
in vitro test results.
Specific allergens
Summary Statement 27: Immunotherapy is effective for
pollen, mold, animal allergens, cockroach, dust mite, and