One of the most famous misdiagnoses occurred recently in New York when a 7-month-old who had contracted cutaneous anthrax was initially diagnosed as having a brown recluse spider bite, even though these spiders are not native to New York. (The Diagnosis of Brown Recluse Spider Bite Is Overused for Dermonecrotic Wounds of Uncertain Etiology)
Two new studies in this issue find new methods to help accurately diagnose brown recluse spider bites. One study unveils the first assay (a Loxosceles species ELISA) that physicians can use to accurately test for the presence of the spider venom in a patient who was possibly bitten. Emergency physicians from the University of Michigan Medical Center in Ann Arbor and a dermatologist from the University of Missouri Health Sciences Center developed the assay. (A New Assay for the Detection of Loxosceles Species [Brown Recluse] Spider Venom)
In another study, a similar University of Michigan team of emergency medicine investigators found preliminary evidence that invasive biopsies may not be necessary to identify suspected brown recluse spider bites. Using the newly developed Loxosceles ELISA assay, the investigators find venom is detectable in hair, fluid from the wound and in skin biopsies in an animal model at least seven days after venom inoculation, but venom was not detectable in serum samples. (Detection of Loxosceles Venom in Dermal Lesions: A Comparison of 4 Venom Recovery Methods)
The study’s authors said although the less invasive collection of venom from a victim’s hair or fluid from the wound contains far less venom then the biopsy, it is clinically irrelevant as long as some venom is detectable to make a diagnosis.
“Cutaneous anthrax, Lyme disease, and various skin infections can mimic a brown recluse spider bite and are often diagnosed as such,” said Sean P. Bush, MD, Loma Linda University School of Medicine in Calif., and co-author of the editorial. “These misidentifications—as in the case of 7-month-old in New York—can mean delays in appropriate care and possibly grave consequences for these patients. The new assay and methods for detection reported in this issue will improve the accuracy of identifying brown recluse spider bites.”
Annals of Emergency Medicine is the peer-reviewed journal of the American College of Emergency Physicians, a national medical organization with nearly 22,000 members. ACEP is committed to improving the quality of emergency care through continuing education, research and public education. Headquartered in Dallas, Texas, ACEP has 53 chapters representing each state, as well as Puerto Rico and the District of Columbia, and a Government Services Chapter representing emergency physicians employed by military branches and other government agencies.
Journal
Annals of Emergency Medicine