Beetle, Moss, Insect, forest floor, earth
Representative image of a beetle on the mossy forest floor. Willfried Wende/Pixabay


  • A young couple came to a clinic with itchy rashes that had comet-like appearance
  • The unique shape was a sign of the bite of the Pyemotes ventricosus mites
  • The mites parasitize beetles but may also attack mammals like horses and people

Pests at home are generally a nuisance. But for one couple in France, their health was also impacted as the beetles that had been eating their furniture also had a mite infestation of their own.

Doctors in Marseille shared the experience of the young couple in a case report in the New England Journal of Medicine.

The couple, a 30-year-old man and a woman, reportedly sought help at a clinic three days after developing itchy rashes on their abdomens. While rashes may not be too specific of a symptom, the woman's actually had a rather unique pattern: some of the pink dots of the rashes had a trail behind them, making them look quite like comets.

This is evidently the tell-tale "comet sign" of the bite of the European straw itch mite (Pyemotes ventricosus). The couple had developed Pyemotes ventricosus dermatitis. The authors shared photos of the rashes in their report.

Pyemotes ventricosus are free-living mites that are so small they can barely be seen by the naked eye. They parasitize and kill the larvae of insects, particularly the common furniture beetle (Anobium punctatum), which is a wood-boring beetle. However, if their normal prey isn't available, then they may attack mammals like horses, cattle and humans.

For instance, people may incidentally get infected if they handle affected wood furniture. While the bites may be painless at first, they eventually develop to be extremely itchy.

In the case of the couple, it turned out that a "beetle infestation was identified in the couple's furniture." And, it appears that the beetles had an infestation of the mites.

As horrifying as the prospect of mite bites may sound, however, there's no need to lose sleep over it because such reports are said to be quite rare. A comprehensive review in 2022 logged 21 outbreaks since the first one was reported way back in 1909 when the crew of a private yacht came in contact with infected straw mattresses. There are also just about 40 individual case reports.

For instance, in 2018, a 51-year-old developed two lesions with the signature comet-like tracks shortly after he handled logs and timber outdoors. And in 2021, an Italian woman who spent time in an apartment with wooden furniture also had it.

Luckily, as annoying and itchy as the bites may be, these pests are not known to transmit diseases. P. ventricosus dermatitis is said to be self-limiting and can disappear in one to three weeks without treatment. Though in the case of the couple, they were given medications including antihistamines.

In some cases, it may also lead to symptoms like fever and vomiting. The condition, however, may be underreported in certain regions, partly because the signature comet sign in the lesions only appears in a quarter of the cases.

The lesions may relapse if the patient gets repeated exposures to an infested environment, researchers of the previous reports said. But in the case of the young couple in France, it seems they made sure to avoid the experience again as they reportedly got rid of their infested furniture.