More and more residents of the northeast United States are becoming aware of the fact that many caterpillar species in the region possess venomous “hairs” that can trigger serious allergic reactions in humans. Some caterpillars in the region, like the invasive Gypsy moth-caterpillar, possess hairs that can trigger dermatitis, but others, like the Sycamore tussock moth, possess hairs that can trigger life-threatening allergic reactions, such as asthma attacks and anaphylactic shock. These “hairs” are called “urticating hairs” and many New World tarantula species possess them as well.

Sycamore tussock moth-caterpillars, and many other venomous caterpillar species, are abundant within forested and residential areas of the northeast, and allergy outbreaks have occured in neighborhoods where venomous caterpillars were prevalent. Venomous caterpillars pose a particularly significant threat to residents who have trees on their property or in their neighborhood. However, venomous caterpillars pose a threat to residents of the northeast in any area where a tree is present. For example, not long ago, a Sycamore tussock caterpillar fell onto a man’s arm as he was entering his car. The man’s car was located beneath a tree in his home driveway, and it was clear that the caterpillar had fallen from this tree. Despite making minimal contact with the caterpillar, the man immediately experienced a host of troubling allergy symptoms, including a rash and an asthma attack.

Within a minute of the man’s caterpillar encounter he developed redness, swelling, pain, and severe itchiness on his left forearm where the caterpillar landed. The man decided to drive straight to the hospital once he began to experience an asthma attack. Before he arrived, the redness on his arm had spread to his chest and neck. The man was treated at the ER and his asthma cleared up within two hours, but his itchy rash lasted for days. Although this man had experienced mild asthma symptoms in the past, he had never experienced significant allergy issues. Those who are allergic to the venomous urticating hairs of the Sycamore tussock caterpillar could go into anaphylactic shock after making contact with the hairs, even if the hairs are no longer attached to the caterpillar. Those who are not allergic to any insect venoms will, at the very least, experience skin irritation after making contact with venomous caterpillar hairs. The Sycamore tussock caterpillar can easily be recognized by its entirely white and fluffy-looking exterior that resembles a cotton ball.

Have you ever experienced inexplicable allergy symptoms that you now think may have occurred due to exposure to a caterpillar’s urticating hairs?