How does Immunotherapy (Allergy Shots) Work?

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Immunotherapy is a process in which an allergic patient can become desensitized to those pollens and inhalants that trigger allergic rhinitis (nasal congestion), allergic conjunctivitis, asthma and insect reactions. Small doses of the actual allergic substance are injected weekly. Each week the dose is increased. Gradually a protective antibody, also known as Immunoglobulin G, is formed to block the allergic reaction. When someone has allergy, they have high levels of the allergic antibody, Immunoglobulin E (IgE), in their blood. This IgE is activated by the allergen (dust mites, ragweed, cat, etc), and it attaches itself to “mast” cells that release histamine. The histamine causes a release of a fluid that causes swelling and congestion. It can cause a tightening of the airways to create asthma.

The change induced by immunotherapy is gradual. Many patients notice an improvement within six (6) months at which time the patient should schedule a 6-month evaluation appointment. Progress is evaluated every six (6) months to one (1) year. Immunotherapy does not work in about 5% of patients who were correctly diagnosed to have significant allergies.

How is Allergy Diagnosed?

The most important diagnostic tool is the history of the illness. The patient’s description of the problem leads to a diagnosis 90% of the time. Skin tests are used to confirm this impression and to define exactly which allergens are involved. For over 75 years skin testing has been the standard method of identifying allergens.

Since 1960 a blood test has been developed which identifies Immunoglobulin E, IgE, in the blood. Experience has shown this method to be less sensitive and less accurate than skin testing.

Moreover, skin tests can be performed at the cost of $6 to $8 per allergen. Blood testing usually costs $20 to $25 per allergen. Because of less accuracy and higher costs, medical insurance plans are currently limiting coverage for the blood test of allergies. This office uses blood tests for patients whose skin reacts to everything and for those who have a strong fear of skin testing.

Who Might Consider Immunotherapy (Allergy Shots)?

Immunotherapy is reserved for patients who have significant hay fever lasting longer than 6 to 8 weeks each year. It is also helpful for asthma, insect allergy and frequent sinusitis. Immunotherapy is not recommended for mild allergies or for food allergies. It is also not useful for less well-defined areas such as intestinal and emotional problems, arthritis, headaches unrelated to sinus problems or hives.

How Long Should Someone Receive Immunotherapy?

A two (2) year period is adequate to assess the success of treatment. If high doses of treatment have been achieved, one should notice a significant improvement in symptoms. Most patients notice significant improvement after the first 6 months.

At year 4 or 5, a trial of discontinuing treatment should be attempted. After immunotherapy is stopped symptoms may return at a rate of 5% in the first (1st) year, 10% in the second (2nd) year and up to 35% in the third (3rd) to fifth (5th) years.

Immunotherapy (Allergy Shots) and Pregnancy

Allergy shots are usually not started for a woman during pregnancy, though there is no medical reason not to do so. The beginning of immunotherapy has the most allergic reactions to the shots (see reactions to shots). If a woman has been receiving immunotherapy and becomes pregnant, she may safely continue the shots during the pregnancy. Immunotherapy has been used for over 75 years and does not harm the baby.

Reactions to Immunotherapy

There are two (2) kinds of reactions to the allergy shot : Local and Generalized (Systemic).

  • Local: Reactions occur at the site of the injection on the arms (“where the shot was given). Redness & itching are frequent and are not a reason to hold or decrease the dose. Swelling or a lump that is irritating is a reason to hold or decrease the dose. This might occur in the office during the 20-minute waiting period or at home over the next 24 hours. Patients are asked to tell the doctor or nurse before the next injection about any swelling. We want to know how large it is…Is it the size of a dime, nickel quarter, half-dollar or larger? We can adjust the dose of future injections. An ice pack and an antihistamine, such as Chlortrimetron or Benadryl, can be used to reduce any swelling. Patients are asked to call the office during office hours to report these reactions.
  • Generalized (Systemic): Reactions occur when there is any chest tightness, breathing difficulty, throat or lip swelling, hives, dizziness or an overall feeling of warmth in the face and body. This usually occurs in the first 10 minutes after the injection but can occur over the first hour. This is a strong reaction, not a minor feeling, which sometimes starts with a general feeling of itchiness. Other times it starts with a tickle or tingling in the throat.

One should return to the office during office hours or go directly to the emergency room for evaluation and treatment of this reaction. If someone else can drive you, this would be best.

Patients are requested to have an antihistamine (available from the nurse or at the desk) with them in the glove compartment of their car. They should be replaced every 6 months.

Drugs not to be taken while on Immunotherapy

If any other physician wants you to take any of the following medications which all contain a family of drugs called Beta Blockers, it is important to notify him/her that you are on immunotherapy and have been told you are not supposed to take them.

** If you are currently taking a Beta-Blocker, please notify your doctor or a nurse.

The following is a list of Beta-Blockers used to treat high blood pressure :

  • Betapace (Solalol)
  • Blocadren (Timolol)
  • Brevibloc (Esmolol)
  • Cartrol (Carteolol)
  • Corega (Carvedilol)
  • Corgard (Nadolol)
  • Corzide (contains Nadolol)
  • Inderide (contains Propanolol)
  • Inderal (Propanolol)
  • Kerlone (Betaxolol)
  • Lopressor (Metoprolol)(Toprol)
  • Lopressor HCT (contains Metoprolol)
  • Lovatol (Penbutolol)
  • Normadyne (Labetolol)
  • Normozide (Alph,Beta)
  • Sectral (Acebutolol)
  • Tenoretic (contains Timolol)
  • Tenormin (Atenolol)
  • Timolide (Timolol)
  • Toprol XL (Metoprolol)
  • Trandate (Labetolol)
  • Visken (Pindolol)
  • Zebeta (Bisoprolol)
  • Ziac (contains Bisoprolol)

Intraocular Beta-Blockers (eye medications) include :

  • Betagan (Levobunolol) (AKBeta)
  • Betatopic (Betazolol)
  • Betatopic S
  • OptiPranolol (Metipranolol)
  • Timoptic (Timolol)
  • Xalatan (Tatanaprost solution)