ImmunoCAP results were positive to a-Gal in 20 of 24 patients with meat allergy and in 20 of 22 patients with positive gelatin skin test results. Test results were negative in all patients with venom allergy (n = 241), nonmeat food allergy (n = 222), and miscellaneous disorders (n = 290). Results: Positive gelatin test results were observed in 40 of 1335 subjects: 30 of 40 patients with red meat allergy (12 also clinically allergic to gelatin), 2 of 2 patients with gelatin colloid–induced anaphylaxis, 4 of 172 patients with idiopathic anaphylaxis (all responded to intravenous gelatin challenge of 0.02-0.4 g), and 4 of 368 patients with drug allergy. In vitro (ImmunoCAP) testing was undertaken where possible. Methods: Adult patients evaluated in the 1997-2011 period for suspected allergy/anaphylaxis to medication, insect venom, or food were skin tested with gelatin colloid. Objective: We describe a prospective evaluation of the clinical significance of gelatin sensitization, the predictive value of a positive test result, and an examination of the relationship between allergic reactions to red meat and sensitization to gelatin and galactose-a-1,3-galactose (a-Gal). "Relationship between red meat allergy and sensitization to gelatin and galactose-a-1, 3-galactose." Journal of Allergy and Clinical Immunology 129.5 (2012): 1334-1342.īackground: We have observed patients clinically allergic to red meat and meat-derived gelatin. I would wait 24 hours to be sure there is no delayed reaction and then administer the MMR. If there is a history of allergy to beef, cow’s milk or pork or inability to eat food items with gelatin, then I would suggest a similar desensitization/graded challenge protocol in hospital. I would then observe for several hours before discharge (total time 5-7 hours). I would be comfortable with initiating an outpatient challenge with oral gelatin beginning with a dose of 3-5 mg (first minute of IV dosing) and increasing 10 fold every 15-30 minute to a dose of 300-500 mg and then doubling every 30 minutes until a cumulative dose of more than 20-30 grams. In summary, if your patient has no history of anaphylaxis to beef, cow’s milk or pork meat, there is a reduced likelihood of anaphylaxis to gelatin. However, extrapolating from the study we could conclude that the dose for an oral challenge could certainly start at the same dose used for the IV challenge in the study, 20 mg, and increase to 400 mg at intervals of every 15 minutes. The Mullins reference refers to gelatin challenge intravenously, which I would not suggest. They also showed that bovine and pork gelatin show extensive in vitro cross-reactivity. The same paper noted that 16% of the beef meat allergic children and 38% of the pork meat sensitive subjects were sensitive by testing to gelatin, and only 4 had a positive in vitro test to gelatin without meat sensitivity. The paper from Bogdanovic et al also associated milk allergy in children with gelatin allergy so you might consider testing for milk sensitivity. I am not aware of delayed reactions occurring from gelatin but the overlap between alpha-gal, collagen and gelatin allergy at least raises the question. Commins group at the University of Virginia uses an intradermal test to identify sensitive individuals with a delayed reaction to mammalian meat due to alpha-gal sensitivity. You could also test for mammalian meat allergy with prick testing and Dr. One consideration would be to test for alph-gal sensitivity since your patient had a systemic response to the vaccination. There is an extensive literature discussing the relationship between gelatin allergy, collagen allergy and 1,3 alpha-gal sensitivity, most of this with bovine products.
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