By Carol Smith, MD
Birmingham Allergy & Asthma Specialists, PC
www.birminghamallergy.com
Two novel forms of anaphylaxis have been defined recently:
1) acute reactions during the first infusion of cetuximab and 2) delayed
anaphylaxis to red meat. In each case,
these reactions were shown to be occurring in patients who had IgE antibodies
to the oligosaccharide galactose alpha-1,3-galactose, which is a mammalian
blood group substance.
In a study published in the April 2011 issue of The Journal
of Allergy and Clinical Immunology (JACI), Commins et al have now reported
evidence that tick bites predominantly from the Lone Star Tick cause these IgE
antibodies. The evidence includes prospective data on three subjects, a strong
association with a history of tick bites, a good correlation (r=0.67,
p<0.001) between IgE antibodies to tick extract and IgE antibodies to alpha-gal,
and finally extensive epidemiological evidence that these IgE antibodies are
only found in areas where tick bites are common. These IgE antibodies are
common (i.e., 15-20% of adults) in an area that includes TN, NC, AR, MO and VA.
These results are important clinically because the cases of
anaphylaxis starting 3-6 hours after eating beef, lamb or pork can be very
confusing. The history usually includes prolonged pruritic reaction to ticks.
The diagnosis becomes probable with positive skin tests to mammalian extracts
and can be confirmed by blood test for IgE to alpha-gal.
This comes from the website of the American Academy of
Allergy, Asthma and Immunology. These novel forms of delayed pruritus,
urticarial and/or anaphylaxis have been elucidated, primarily through research
done in the Allergy Department of the University of NC, Chapel Hill. We have
diagnosed several cases here at the Birmingham Allergy & Asthma Clinic, but
many more cases likely go undiagnosed. Please let us know if you have any
patients with delayed or unexplained anaphylaxis, or questions about this very
interesting phenomenon.
CAROL SMITH, MD
Birmingham Allergy & Asthma Specialists, PC
www.birminghamallergy.com
My husband died last year because of having tick bites and being given Erbitux. We live in GA. Patients need to be told about this allergy. Erbitux should not be used in the southeast - it is too dangerous and what is even worse. The drug maker knows about this and have known since 2008 when Dr Platts-Mills discovered the allergy and TOLD them.
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