Immunotherapy for Allergies Periprocedural Care

Updated: May 01, 2017
  • Author: Benjamin Daniel Liess, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
  • Print
Periprocedural Care

Patient Education & Consent

Refer patients to the Web sites of the American Academy of Allergy Asthma & Immunology or America's College of Allergy for allergy and dustproofing information.

Companies including National Allergy Supply and the Allergies Buyers Club have information and products available for purchase to augment allergy control and treatment.

Patient Instructions

Prior to each allergy shot, it is recommended that the health care provider confirm that no reaction occurred during the preceding shot, the patient has begun no new medications, (particularly beta-blockers), and that asthma, if present, is stable via peak flow measurement.

Elements of Informed Consent

Any medication (including beta-blockers) or health contraindications (eg, loss of asthma control) should be identified.

Duration of treatment and symptom control should be discussed.

Patients who become pregnant while on immunotherapy may continue treatment; however, commencing immunotherapy in pregnant women is not advisable. Some authors do not advance immunotherapy in pregnant women until the postnatal period. [29]

Subcutaneous immunotherapy should be initiated only in patients willing and able to comply with weekly injections for a year or longer. Once maintenance is reached, the injection regimen may become less frequent; however, several years’ duration is commonly required for clinical efficacy.

Sublingual immunotherapy is appropriate for patients who are unable to commit to weekly injections or those who do not want injections.

Interestingly, a 2013 study by Kiel et al demonstrated that long-term adherence favored subcutaneous immunotherapy over sublingual immunotherapy. [30]

Next:

Pre-Procedure Planning

Choosing antigens to treat with immunotherapy

Careful consideration must be given to the timing and location of symptoms when choosing antigens to treat. For example, a patient with spring-only symptoms who allergic to trees and ragweed may not require immunotherapy for ragweed. A patient with symptoms that occur only when visiting homes where cats live may not require treatment for their pollen sensitivities. Testing should be based on a patient’s specific allergen exposure. [31]

Cross-reactivity

Several inhalant classes contain different species that are cross-reactive, so treating with one of the antigens is sufficient. Only one of the pooid grasses, for example, (most often timothy) is usually included in a patient’s mix. Similarly, the Olive-Ash family may not require treatment of all antigens.

The existence of cross-reactivity to panallergens such as profilins, similar in many species but not the actual instigators of allergic reactions, could lead to unnecessary inclusion of these inhalant antigens.

Starting dose of immunotherapy

The starting dose can be (1) the same dilute dose for all antigens, (2) based on backwards calculation from the target maintenance dose, or (3) based on semiquantitative testing such a intradermal dilutional testing or radioallergosorbent test (RAST) or ImmunoCAP (ICAP) classes.

Equivalent initial dose for all treated antigens

Most allergists/immunologists and many otolaryngic allergists use an initial dose equivalent for all treated antigens. Using either 5- or 10-fold dilutions of the antigen concentration supplied by the manufacturer, 4-6 vials of increasingly weaker antigen are prepared. Treatment is started with a very small dose from the weakest vial, works up to a larger dose from this vial, and continues to a very weak dose from the next-strongest vial. Many allergists modify the dose increase upon a significant local reaction, some evidence has shown that this is unnecessary. [32] A reasonable starting dose for most patients is 0.5 mL of a w/v concentration of 1:200,000-500,000.

Quantitative-based initial dose

Some otolaryngic allergists use a quantitative-based initial dose. Intradermal skin testing is performed with increasing concentrations of each antigen, beginning with a sixth 5-fold dilution from manufacturer’s concentrate (typically 1:20 w/v), yielding a 1:312,500 w/v concentration. The concentration at which the patient first develops at least a 7-mm wheal is used as the beginning treatment dose. For example, a fourth 5-fold dilution from concentrate would give a concentration of 1:12,500. If this is the point at which the first clinically significant skin reaction occurs, this is the concentration of this antigen used in the initial treatment vial.

The theoretical advantage of this approach is that antigens to which the patient is more sensitive are started at a lower dose and those to which the patient is less sensitive are started at a higher dose. Theoretically, this minimizes problems with escalation caused by large local or systemic reactions to the most sensitive antigen. There have been no head-to-head studies comparing this technique to the traditional approach.

Mixing inhalant immunotherapy vials

When mixing a vial for immunotherapy, if the final desired dose is the starting point, this is figured for each antigen in the treatment vial. In general, this will be 5-12 µg per dose. Since beginning immunotherapy with the desired final concentration would likely result in significant systemic reactions, dilutions are prepared from this concentration to begin with a very weak concentration. This is gradually increased as tolerated by the patient’s body until the desired final treatment dose is reached.

Some insect and fungal antigens contain high levels of protease, which can potentially degrade pollen proteins, causing more rapid than expected loss of bioactivity. Some physicians recommend always separating insect and fungal antigens into a different vial from pollen antigens to prevent this happening.

Vial test

Some practitioners suggest that a useful safety measure is injecting a small dose of each new vial intradermally, where there are more reactive cells. The development of an unexpectedly large wheal from this technique may suggest that it may be prudent to dilute this vial further before beginning usual subcutaneous injections.

Using this technique, a 4-mm intradermal wheal is placed and observed for 10-20 minutes. If the resultant wheal is smaller than 13 mm, the first dose is given. If the wheal is 13 mm, retest in a few days. If the wheal increases to larger than 13 mm, consider diluting the vial. If using 1:5 dilutions, this is performed by taking 1 mL from it and adding it to 4 mL of diluent. This new dilution is then vial tested.

Previous
Next:

Equipment

See Complication Prevention.

Previous
Next:

Monitoring & Follow-up

Should anaphylaxis to immunotherapy occur, the management in an inpatient setting may be appropriate.

The treatments described above may be used to provide control of allergic symptomology. A history and physical examination should be performed at least annually by treating physicians once the patient has achieved maintenance on immunotherapy. While not dogma, some physicians recommend that patients have up–to-date EpiPens for use as needed, especially if the patients are administering their own allergy shots at home.

Previous