**Abstract:**  
  
Allergen immunotherapy is defined as the repeated administration of specific
allergens to patients with IgE-mediated conditions, for the purpose of
providing protection against the allergic symptoms and inflammatory reactions
associated with natural exposure to these allergens.  
  
Immunotherapy (hyposensitization) may extend over a period of years, usually
on an increasing dosage scale. This is followed by a build-up of tolerance to
the antigen (as evidenced by the markedly higher doses that can be
administered) and a decline in the symptoms and medication requirements of the
patient. Indications for immunotherapy are determined by diagnostic testing
appropriate to the individual needs of each patient and his/her clinical
history of allergic diseases.  
  
Allergen immunotherapy should be differentiated from the process of
desensitization, which usually applies to the rapid progressive administration
of an allergenic substance to render effector cells less reactive.  
  
The technique of allergen immunotherapy should also be differentiated from
unproven techniques such as neutralization-provocation therapy. Optimal dosing
for sublingual swallow and oral immunotherapies is under clinical
investigation in the United States but remain investigational at this time.  
  
This LCD documents CGS indications and limitations of coverage for these
procedures  
  
 **Indications:**  
  
Indications for immunotherapy are determined by appropriate diagnostic
procedures coordinated with clinical judgment and knowledge of the natural
history of allergic diseases.  
  
Controlled studies have shown that allergen immunotherapy is effective for
patients with allergic rhinitis or conjunctivitis, allergic asthma, and
stinging insect hypersensitivity.  
  
Allergen immunotherapy is indicated for patients who show demonstrable
evidence of specific IgE antibodies to clinically relevant allergens and whose
allergic symptoms warrant the time and risk of allergen immunotherapy. The
necessity of initiating allergen immunotherapy may also depend on the degree
to which symptoms can be reduced by medication, the amount and type of
medication required to control symptoms, and whether appropriate avoidance is
possible.  
  
Allergen immunotherapy is indicated for patients with a diagnosis of allergic
asthma, allergic conjunctivitis, allergic rhinitis, or stinging insect
hypersensitivity depending on the results of allergy testing (immediate
hypersensitivity skin tests or in vitro tests for specific IgE). There is
limited data indicating that it may be effective in atopic dermatitis when
this condition is associated with aeroallergen sensitivity. Immunotherapy
should not be given to patients with negative results for specific IgE
antibodies or those with positive test results for specific IgE antibodies
that do not correlate with suspected triggers, clinical symptoms, or exposure.
Immunotherapy is effective for pollen, mold, animal allergens, cockroach, and
dust mite.  
  
Venom immunotherapy is indicated for patients who have anaphylaxis after an
insect sting and a positive skin test or other documented IgE sensitivity to
specific insect venom. Patients with delayed systemic reactions with symptoms
of anaphylaxis or serum sickness and with a positive skin test or presence of
venom specific IgE by in vitro testing are also recommended for treatment.  
  
Rapid desensitization is indicated in cases of allergy to insulin, penicillin
and horse serum, as well as sulfonamides, cephalosporins and other commonly
used drugs. In patients with a positive history of reaction and with
documented skin test reactivity, every effort should be made to avoid the use
of these substances. When circumstances require the use of one of these
substances, the patient will have to be desensitized. Full-dose therapy should
be initiated immediately after reactions (treated and controlled), requiring
strict physician monitoring in a setting with continuous monitoring of vital
signs and cardio-respiratory status. In most cases, this can be performed in a
physician's office if a physician trained to treat anaphylaxis is physically
present for the entire duration. In cases where the initial reaction was
severe, desensitization should be performed in the ambulatory care department
of a hospital.  
  
Desensitization may need to be repeated if future circumstances require an
additional course of the offending allergen. Rapid desensitization in the form
of rush immunotherapy may also be appropriate for venom, pollen, dust mite,
mold and dander.  
  
Standardized dust mite extracts appear effective for immunotherapy. Other
environmental allergens (e.g., kapok, jute, feathers, and unstandardized house
dust extracts) are of questionable value in immunotherapy, however, and
generally should not be used.  
  
Animal dander sensitivity (epidermal) may respond to immunotherapy. While
removal of the offending allergen is recommended, this is often not possible
or there may be occupational or other sources of exposure. Therefore, a trial
of immunotherapy may be warranted.  
  
Allergen-induced asthma is an indication for immunotherapy along the
guidelines for allergic rhinitis when there is a poor response to
environmental control or pharmacologic treatment.  
  
 **Limitations:**  
  
Allergen immunotherapy is divided into codes that describe the injection only
and codes that describe the preparation of the antigen to be delivered for
injection by a different physician.  
  
SUPPLY OF ANTIGEN  
  
Payment may be made for a reasonable supply of antigens that have been
prepared for a particular patient when:

  * The antigens are prepared by a physician who is a doctor of medicine or osteopathy; and
  * The physician who prepared the antigens has examined the patient and has determined a plan of treatment and a dosage regimen.

Antigens must be administered in accordance with the plan of treatment and by
a doctor of medicine or osteopathy or by a properly instructed person under
the supervision of the doctor.  
Effective January 1, 2001, the Centers for Medicare and Medicaid Services
(CMS) revised the regulation limiting the supply of antigens that can be
prepared by a physician for a particular patient at one time. The limitation
is changed from a 12-week supply to a 12-month supply. This regulation is
revised with the stipulation that it is a physician's responsibility to
furnish only a supply that would remain stable and potent over the time period
for which they are administered.  
  
TREATMENT SCHEDULES  
  
The starting dose of an allergenic extract and the progression of the dose
must be individualized for each patient. The Immunotherapy build-up schedule
entails administration of gradually increasing doses during a period of
approximately 14 to 28 weeks. In conventional schedules a single dose increase
is given on each visit, and the visit frequency can vary from 1 to 3 times a
week. Accelerated schedules such as rush or cluster immunotherapy entail
administration of several injections at increasing doses on a single visit.
Accelerated schedules offer the advantage of achieving the therapeutic dose
earlier but might be associated with increased risk of systemic reaction in
some patients.  
  
LENGTH OF THERAPY  
  
The duration of all forms of immunotherapy must be individualized. A
presumption of failure can be made when, after 12-24 months of therapy, a
person does not experience a noticeable decrease of symptoms, an increase in
tolerance to the offending allergen and a reduction in medication usage.  
  
Treatment will not be reimbursed after a 2-year period when there is no
apparent clinical benefit.  
  
The major risk of allergen immunotherapy is anaphylaxis. Allergen
immunotherapy should, therefore, be administered under the supervision of an
appropriately trained physician who can recognize early symptoms and signs of
anaphylaxis and administer emergency medications where necessary. In addition,
immunotherapy should be administered only in facilities equipped to treat
anaphylaxis.  
  
It may be appropriate to permit patient self-administration at home for the
rare patient with life-threatening anaphylaxis who cannot receive
immunotherapy in a health care facility (e.g., venom immunotherapy for a
patient living in a remote area)). This requires very careful consideration of
potential benefits and risks and should be made on an individual patient basis
with appropriate informed consent.  
  
The following services are considered investigational and will not be covered.

  * Desensitization with commercially available extracts of poison ivy, poison oak, or poison sumac.
  * Desensitization for hymenoptera sensitivity using whole body extracts, with the exception of venom extracts and fire ant extracts.
  * Desensitization with bacterial vaccine (BAC: bacterial, antigen complex, streptococcus vaccine, staphylo-strepto vaccine, serobacterin, staphylococcus phage lysate).
  * Food allergenic extract immunotherapy.
  * Intracutaneous desensitization (Rinkel Injection Therapy, RIT).
  * Neutralization therapy (intradermal and subcutaneous).
  * Repository emulsion therapy.
  * Sublingual desensitization.
  * Sublingual provocative therapy.
  * Urine autoinjection (autogenous urine immunotherapy).
  * Allergen immunotherapy for the management of skin and mucous membrane disease such as urticaria, and Candida vulvovaginitis.

Patients who are mentally or physically unable to communicate clearly with the
allergist and those with a history of noncompliance are not good candidates
for allergy immunotherapy.  
  
Medicare will not cover antigens provided for sublingual administration. This
type of therapy has not been proven safe and effective.  
  
Immunotherapy with whole-body extracts of biting insects or other arthropod
(95170) is covered only for fire ant extracts.  
  
Evaluation and management codes are separately reimbursable on the same day as
allergen immunotherapy only when a significant, separately identifiable
service is performed.