Carpet Beetles in Kindergarten

By Marcia Anderson

A few weeks after summer recess, some preschool and kindergarten students came into their school nurse’s office with red welts on their legs. The bites were large, itchy, and had a burning sensation. The problem escalated until a few students from different classrooms, had over 20 red welts on their legs. Some students seemed to be bitten daily, while others in the same classrooms had no bites at all. The students began to recover on long weekends, but got worse when they came back to school. This continued for two months.

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Mosquitoes, lice, fleas, spiders, bed bugs? The usual culprits were eliminated one-by-one. The nurse reported the problem and a pest management professional (PMP) was deployed to investigate. The PMP suspected carpet beetles instead of bed bugs due to the fact that some children were being bitten while others were not. Some people are allergic to carpet beetles and some are not; however, almost everyone has some sensitivity to bedbugs. Upon inspection the PMP found carpet beetles but no bedbugs.

Carpet beetles are similar to bedbugs in that they are tiny, hard to find, and most active in the wee hours of the morning. The difference is that bedbugs bite, but carpet beetles do not. Carpet beetles eat natural fibers, like wool blankets and feathers, and naturally occur in most homes.

Through further investigation the nurse discovered that the reading areas in all six affected classrooms had their carpets replaced over the summer with new carpets made from mostly natural fibers.

When children walk or move around on the carpet, especially on dry days, there may be a build-up of static electricity that causes the fine hairs cast off the carpet beetle larvae to pass though all but the finest of weaves of clothes. In these classrooms, it appears that static caused the carpet beetle hairs to impale themselves in the surface of the children’s skin, thus creating small pin prick wounds that looked similar to insect bites. Carpet beetles cause a medical condition where the piercing of the skin causes a reaction, either as a result of the insertion of a foreign object (the hairs) into the skin or as a reaction to pollution that enters the open wound.

Anthrenus_verbasci_-_larva_front_(Andre Karwath)

The most commonly found form of carpet beetle is the larvae, which are often termed wooly bears. They are small hairy caterpillars, the skins of which can often be found in dark places. Perhaps they originated from the enclosed, dark conditions in the warehouse where the carpets were stored.

The good news is that no chemical treatment was necessary as it was not the live insects causing the allergic reaction but their prickly little hairs. The solution was to make sure all the allergens (the hairs) were removed from the carpets. The school had the carpets vacuumed with a HEPA vacuum then steam cleaned. The problem was solved.

Read a 2012 story on carpet beetles.

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