Two species of processionary caterpillars were classified as harmful to health in a decree published on April 27. In case of contact with humans or pets, their hair can trigger a violent hives reaction.
They are small hairy insects whose hairs come to nest in the skin. On April 27, a decree issued by the government classified two species of processionary caterpillars, that of the pine and that of the oak, as harmful to human health. And for good reason. Between January 2012 and December 2019, the National Agency for Food, Environmental and Occupational Health Safety identified 1,274 cases of affected people.
“They have hives that will come off, so there’s not even a need for direct contact. Like little darts, they will nestle in the skin. This causes red patches, hives, sometimes it can affect the eyes”, analyzes Professor Marie-Sylvie Doutre, dermatologist at the Bordeaux University Hospital and member of the French Society of Dermatology.
Processionary caterpillar season is currently in full swing, marked by the moment when they leave the trees, where they were housed in conspicuous white cocoons on the branches, to flee into the ground. Marie-Sylvie Doutre returns for BFMTV.com on the actions to adopt in the event of contact with this species.
• To protect yourself, wear long clothes
The best protection is prevention. While processionary caterpillars are dangerous during their migration, it is important to dress well when walking in the forest or even in a park. Once on the ground, the caterpillars move in a long line in the form of a procession, hence their name.
“You have to wear shirts, pants, closed shoes and not go out in flip-flops! And when you come home, you have to wash them and then put them in the washing machine and the dryer,” advises Marie- Sylvie Doutre.
Similarly, the specialist recalls when in the south-eastern regions, some people prefer not to dry their laundry outside, for fear that the wind will come and deposit the famous urticaria hairs of the caterpillars.
• Antihistamines and cortisone cream
If, despite these precautions, you end up coming into contact with the caterpillar, you risk developing hives and, in some cases, an eye infection. How to react in this kind of situation?
First, it is important to emphasize that in the vast majority of cases, these kinds of symptoms, although unpleasant, are not dangerous, and disappear after a few hours or even a day. To calm the itching, Marie-Sylvie Doutre mentions taking antihistamines and applying creams with cortisone.
A medical consultation is not systematically necessary. However, if the symptoms persist, or in case of contact with the eyes, but also if respiratory disorders appear, it is advisable to consult. In very rare cases, the infected person may develop anaphylactic shock.
• Watch out for animals and children
Adults are not the people most at risk. Children and pets, especially dogs and cats, on the other hand, may develop more severe symptoms because they are more likely to come into direct contact with the caterpillars. A dog or a cat by sniffing the insect or by touching it with the paw, a child by catching it with bare hands.
“For children, who touch caterpillars and then rub their eyes, it may be necessary to consult an ophthalmologist to remove hair from children’s eyes”, warns Marie-Sylvie Doutre.
As for the dogs that would be brought to sniff or lick the caterpillars, there too, they can develop a significant allergic reaction, even an anaphylactic shock. It is advisable to consult your veterinarian urgently.
• An extended presence in the territory
Advice that is all the more topical as the area of activity of processionary caterpillars now extends over the entire territory. “Even in the parks around Paris”, assures Marie-Sylvie Doutre. In question? Global warming.
“I conducted a survey about ten years ago. Already at that time, the area of action of processionary caterpillars was increasing,” she says.