Anaphylactic Reaction to Subcutaneous Immunotherapy in a Patient with Asthma: How Do You Change the Dose?

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology

A 16-year-old CF is on a maintenance dose of subcutaneous immunotherapy (SCIT) for allergic rhinitis and asthma. She receives the injections by in her primary care physician office in a different town and the allergy clinic prepares the mixtures. The immunotherapy prescription consists of trees, grasses, dust mite, cat, dog and cockroach. She has been on a maintenance dose (injections given every 3 weeks) for 1.5 years and has had several episodes of large local reaction. Three dose ago, she had an URI with mild fever but still went for her "allergy shot." There was a new nurse who administered the injection "higher than usual" in the area of the deltoid muscle. Within 2-3 minutes, she developed shortness of breath, wheezing and desaturation in the 80s. She was treated with an EpiPen, prednisone, loratidine and albuterol inhalation. Her condition improved and after an evaluation in th ED, she was discharged home.

Past medical history (PMH)

Allergic rhinitis and conjunctivitis, asthma.


Flovent 110 mcg INH bid, Fluticasone (Flonase) 50 mcg/actuation nasal spray QHS, loratidine 10 mg po daily.

Social history (SH)

No tobacco or alcohol use.

Family history (FH)

Mother with asthma and allergic rhinitis.

Physical examination


What is the most likely diagnosis?

Anaphylactic reaction to SCIT.

What is the most likely reason for the anaphylactic reaction?

Patients with asthma are at higher risk for fatal anaphylactic reactions. Virus infections and febrile conditions create and inflammatory evnironment that could have contributed to her anaphylactic reaction. The injection in the area of the deltoid muscle could be inadvertently administered IM instead of SC, especially of the personnel is inexperienced.

How would you change the SCIT dose?

She currently receives 0.4 ml of the 1:1 dilution. SCIT dose was decreased by "two dilutions" - to 0.4 ml of dilution 1:100.

She was advised to receive the next SCIT dose in our office and to consider receiving the following doses at an allergy clinic in her home town rather than at her PCP's office.

Final diagnosis

Anaphylcatic reaction to SCIT.

What are the 4 standardized allergen extracts?

(A) Dog
(B) Trees
(C) Cat
(D) Molds
(E) Dust Mite
(F) Grass
(G) Ragweed

The 4 standardized extracts are Cat, Dust Mite, Grass and Ragweed.


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Published: 03/20/2009
Updated: 01/20/2011

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