Phoenix Woman Had Marble-Sized Blisters From Beetle Bite

PHOENIX, AZ — A Phoenix woman was hospitalized after she was bitten by a blister beetle that caused marble-sized welts on her arm and excruciating pain. When threatened by predators, the colorful, plant-feeding beetles emit cantharidin, a defensive toxic chemical that protects them.

Dr. Joanna Woods said she was bitten at a movie theater and initially dismissed the source as a mosquito or bed bug. But the pain from the bite intensified and the welt grew, so she sought medical help.

It didn’t feel like any itch she had ever experienced.

“It’s like I put my arm in a skillet and couldn’t take it off,” Woods told television station KNXV of the pain resulting from the blister beetle bite.

Woods first went to the pharmacy to get an ointment for the painful bite and was referred to urgent care, where the physician said she should go to the emergency room. There, the staff was initially mystified. (Get Phoenix Patch's real-time news alerts and free morning news letters. Like us on Facebook. Also, download the free Patch iPhone app or free Patch Android app.)

“I had nurses in there saying, ‘I’ve been doing this for 35 years, I’ve never seen this, what is it?’ ” Woods told the television station.

Woods spent two days in the hospital because of concerns about the size of the blisters and treatment for infection.

The colorful, winged “master blister beetle” is common in Phoenix. Arizona State University describes it as “one of the biggest and fanciest blister beetles anywhere” and said it can grow up to a couple of inches long.

They are most commonly found in the springtime when brittlebush, a common desert shrub, is flowering. A single bush may house several dozen of the beetles, which may dangle from the plant’s flower stalks.

Even if they’re squashed, the chemical they emit may remain active for two or three months after they’re dead, Scorpion King Exterminating owner Eric Godinez told KNXV.

Photo by Shutterstock / Angel DiBilio