What Is a ‘Tick Bomb’ and Does It Cause Disease?

If one tick bite seems bad enough, imagine a whole explosion of them latching onto an ankle or crawling up a leg at once.

This is known as a “tick bomb,” which occurs when a human or animal steps on a tick nest, and hundreds or thousands of larval-stage ticks grab on at once.

They’re so tiny, they would be very difficult to see individually. But as a group, it’s hard to miss them wriggling around in one itch-inducing mass.

In the U.S., only lone star tick larvae will bite humans and create a tick bomb, said Jonathan Oliver, PhD, a public health entomologist who specializes in vector-borne diseases at the University of Minnesota in Minneapolis.

“Females can lay clutches of about 1,000 to 2,000 eggs, so if you step right onto that spot, or worse, sit down on it, those ticks are going to be all over you all at once,” Oliver told MedPage Today. “And they bite.”

Luckily, for the most part, larval lone star ticks won’t transmit bacterial diseases because they haven’t yet had a blood meal to pick up other pathogens, Oliver said. Unfortunately, there is some evidence that mothers can pass viruses to offspring — and lone star ticks are known to carry some troublesome ones, such as Bourbon virus and Heartland virus — but it would be very rare for someone to get infected this way, he noted.

Alpha-gal syndrome, however, would be a risk: “It has been shown that unfed larval lone star ticks carry the protein that can cause alpha-gal in people,” Oliver said, adding that the prevalence of the red meat allergy is on the rise across the U.S., as the lone star tick expands its range.

With climate change, it’s only expected that this range will grow, he noted. Clinicians in the South and Southeast U.S. may be acquainted with “tick bombs,” but as the tick becomes more prevalent in the Northeast, Midwest, and New England, clinicians there may see more patients with tick-bomb bites.

Not all clinicians may be able to identify such bites. One nurse practitioner in North Carolina recently shared on Reddit what many commenters believed to be a rash due to a tick bomb. A 70-year-old patient initially thought an intensely pruritic rash was due to mosquito bites, but it continued to spread up her legs over the course of about 2 weeks.

On examination, the patient had scattered papules and vesicles in various stages of healing. While the nurse practitioner initially thought the lesions had hemorrhagic crusts, “upon closer inspection, I found that the crusts appeared to be moving,” she wrote in her post.

She and her team examined the insects under a microscope and decided they might be lone star tick larvae. It was a strange enough case that the nurse practitioner posted the images on Reddit and asked if anyone else had run into it in practice, but few had. Some suggested treating with permethrin cream.

Oliver noted, however, that the image of the tick appears to be more consistent with a brown dog tick.

“Brown dog ticks are the only species of tick that can reproduce inside of a house, and it sounded like this woman had a longer-term condition,” he said. “I think she most likely had a tick infestation in her house and she was exposed over and over again. It’s an unusual circumstance.”

Regardless of what type of tick it was, it’s still not something anyone wants to experience: “No one wants a tick bomb on their ankle,” Oliver said.

While lone star tick larvae are most prevalent in the summer, they can be encountered at any time during the year when ticks are active, he pointed out.

Indeed, one wildlife biologist in Florida just posted a video of a tick bomb that exploded on his arm. And a marine biologist from Long Island, New York, has posted at least two recent encounters with tick bombs — one in mid-September and another last week, both while checking trail cameras. He captured the ticks with sticky tape wrapped around his boots, which “stopped [them] in their tracks, while my permethrin-treated clothes kept the rest from getting any farther.”