We reached out to Dr. Kevin Kelly, Professor and Interim Chair of Pediatrics at the University of North Carolina. Please find his responses to your questions below.
Q1 – A medical history and a positive Immunocap to latex at this level has a >98% specificity when the level is above 0.64 kU/L in the patient having symptoms of latex allergy. That suggests this patient is at high risk of severe anaphylaxis from exposure to a latex balloon on a catheter when contact is made in the GI tract. I have included the reference below regarding concordance of skin test, clinical history, and serum testing. It turns out that the Immunocap has a modestly low sensitivity but when it is positive in conjunction with symptoms upon exposure to latex, the predictive value is extremely high. THUS, there is no added value to doing a skin test in the US especially when there are significant reports of adverse reactions to skin testing. Also, recall that some of the first reports of 9 deaths (approximate) reported to FDA from anaphylaxis (in retrospect due to latex and not barium) came from balloon tipped barium enema catheters. These were known as the EZM catheters.
Q2. There is no satisfactory evidence that pretreatment with antihistamines and steroids will stop an IgE-mediated anaphylactic reaction although it may lessen the severity and delay the onset of full blown symptoms. Since I am not a surgeon or GI physician, I would wonder if there was not another approach to the care of this patient without using such catheters. I certainly recommend as much precaution as possible and an attempt to stop all latex exposure.
Kelly KJ, Accetta D, Klancnik M, Wang M, Hoffman R, Elms N, Kurup V: Analysis of Available Diagnostic Tests for Latex Sensitization in an At-Risk Population. Annals of Allergy, Asthma and Immunology. 2012; 108(2):94-97
Chiu A, Kelly KJ, Thomason J, Otte T, Mullins D, Fink JN: Recurrent vaginitis as a manifestation of inhaled latex allergy. Allergy 1999; 54:183-90
Jacqueline A. Pongracic, MD, FAAAAI