Could you identify a black widow spider bite if you saw one?
Parents are nervously asking themselves that question after hearing that a 5-year-old Mendon girl is recovering from a black-widow bite on her leg. With temperatures soaring and kids outdoors, the season for insect bites — from spiders, ticks, and other creepy crawlies — is upon us. And black widows, previously rather low on the list of parental concerns, are crawling ever-so-slightly higher.
So how worried should you be?
Mark Waltzman, a senior associate in Medicine, division of Emergency Medicine, at Boston Children’s Hospital, cautions that only a few kinds of spiders in any region are “medically significant,” or harmful to humans. The vast majority of the more than 100,000 species around the world are relatively harmless.
In this region, Northern black widows are the best-known venomous spiders, but they aren’t all that common in Massachusetts, Waltzman says. The brown recluse, found primarily in Texas, Louisiana, and Arkansas, is extraordinarily rare in the Northeast but can arrive as a stowaway in moving crates and containers.
Far more common here — and significantly less dangerous than the black widow — is the yellow sac spider, which carries a cytolytic toxin that can cause tissue death, or necrosis.
Regardless of what kind of spider does the biting, doctors can have difficulty identifying the culprit without seeing the critter itself, says Waltzman, who also an assistant professor of Pediatrics at Harvard Medical School.
“There’s lot of things that look like spider bites that actually aren’t spider bites,” he notes, including poison ivy or oak, skin ulcers, even wounds from a different kind of arthropod.
In the Mendon case, the bite first looked like a “tiny bruise,” according to Kristine Donovan, mother of 5-year-old Kaitlyn, but grew to a large red line over several days. By the time Kaitlyn was admitted to UMass Memorial Medical Center days later, the wound was turning purple and black, a result of what looked to be necrotic tissue around the bite.
While these kinds of spider bites can be quite nasty (and in the case of black widows, deadly), the good news is that both types generally only bite when they feel threatened.
“With black widows, it’s the female that bites, but they’re only aggressive if provoked,” Waltzman says. They’re trapper spiders, meaning they snare prey in their webs, which tend to be located in dark, undisturbed areas like woodpiles or sheds. Yellow sac spiders also tend to hide out — in piles of clothing, for example — and will bite if disturbed.
The spot of a black widow bite will turn red and swell, usually resulting in a blister that will grow. Another symptom: Because black widow venom is a neurotoxin, a bite can bring on muscle spasms. If you think your child may have been bitten, get medical help immediately.
So, besides looking out for themselves, parents should make very sure kids aren’t rooting around in dark corners of the garage or in that old pile of firewood. It’s not a bad idea to shake out the laundry, either. Because the truth is that kids, because of their smaller size, are a greater risk if they get bitten by a dangerous spider.
“The smaller you are physically,” Waltzman says, “the worse the symptoms.”Hayley Kaufman can be reached at firstname.lastname@example.org.