Mid-summer is the peak season for rove beetles, a very small insect that can penetrate the holes of a screen window and cause a very painful chemical burn mark about the size of a person’s palm when it is crushed on the skin, doctors warned.
According to Wu Nan-lin (吳南霖), a dermatologist at Hsinchu’s Mackay Memorial Hospital, the number of patients being treated for wounds caused by rove beetles has increased by more than 50 percent in the past two months.
He warned the public not to crush the insects if they are found inside the home, to avoid skin contact with its irritant, pederin.
He said he recently treated a resident of Hsinchu surnamed Chen (陳) who is in the habit of keeping the lights in his bathroom on when he sleeps at night.
An insect apparently flew into his armpit and was crushed one night last week. Chen said his armpit began to hurt the next day and medicine did not make it feel any better as the wound became red and swollen and the skin started flaking. The pain felt as if the skin were being cut by a knife and sprinkled with salt, he said.
“That’s a typical rove beetle wound,” Wu told him when he sought medical advice.
The insect is very small, making it hard to take precautions against, Wu said, adding that people should go to the doctor immediately if their skin is exposed to the pederin, and avoid applying medicine on their own because it sometimes causes infections or leaves scars, rather than healing the wound.
Wu said rove beetles are categorized in the Coleoptera order of insects, with a body length of about 1cm and width about 2mm, and shaped like a termite, but colored orange-yellow. They usually inhabit rice paddies, grassland and forests, appear between April and October, and are attracted to light when it is dark, so they will fly into lit homes.
Serious skin inflammation results from contact with pederin, usually the result of crushing the insect or touching a dead insect that has been crushed, causing blisters, burning and severe pain.
Wu suggests that people not leave their lights on when sleeping and keep their windows closed at night because screen windows cannot keep the insect out.
People should blow or use objects to remove the insect and refrain from crushing it, and wash their clothes thoroughly and separately if stained with the pederin, he added.