Oak Processionary Caterpillar

 By: USAG Schinnen Public Affairs


The Oak Processionary Caterpillar lives in oak trees in the caterpillar stage from May through July. The hairs on this caterpillar contain an irritant to human skin which commonly causes a skin rash and if inhaled can also cause irritation.

They’ve been found around Schinnen pond on USAG Schinnen. Local authorities report they’ve also been spotted around the Tri‐Border community. They live only on oak trees and are alive May thru July; in July, they cocoon and metamorphose into butterflies, which are harmless.

Do not disturb the nest or cocoons; the same fibers that cause harm if you touch the caterpillar are used to make up the nest/cocoon; disturbing the nest/cocoon releases the fibers, they become airborne and affect much wider territory, causing the same skin rashes and additional respiratory complications if breathed.

The caterpillar continually sheds fine hairs that contain the irritant and the hairs become airborne. In
most cases, these fine hairs land on your skin which causes the rash. In fewer cases, the hairs may land
in your mouth or eyes and you will experience symptoms other than a rash (see below). If you notice
you have been exposed try to rinse off as many hairs as possible rather than trying to wipe them off. It is very likely that you will not notice exposure because the hairs are so fine.

The most common symptoms are the itchy rash and dermatitis (inflammatory condition of the skin). This rash may consist of flat discolorations or raised bumps on the skin. If the caterpillar hairs come in
contact with your eyes or mouth, you may also experience conjunctivitis (red eyes, sticky discharge,
inflammation of the eye) and/or irritation to the throat/airway. Itching typically begins 2‐12 hours after
exposure and the rash may be widely spread over the entire body.

Typically the rash lasts up to two weeks; the irritation can be relieved with over‐the‐counter ointments
containing aloe vera or menthol. If these remedies do not provide sufficient relieve, please make a
medical appointment. If you experience any other symptoms then a rash, please make an appointment
to seek a health care provider. If you are experiencing difficulty breathing or chest pain, please seek
medical attention immediately.

These hairs may be present in the environment through the month of July.  Restricting outdoor activities near oak trees will reduce the concentration of the caterpillar hairs you are exposed to. When
participating in outdoor activities, use personal protective measures to reduce your contact with the
hairs, such as wearing long clothing and a hat. Frequent laundering of clothing worn outdoors will also
reduce your repeated exposure to the hairs that maybe in your clothing.

One Response to “Oak Processionary Caterpillar”

  1. Brianna Brown June 14, 2010 4:16 pm #

    While living in Spain we had these as well… I would like to add they can be very poisonous to Dogs and Cats! My friends dog lost a 1-cent size piece of his tongue from licking one! Check your yards frequently and burn those you find (to avoid hairs becoming airborne) – this was the recommendation from Command in Spain.

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