Processionary caterpillar bite: symptoms and what to do


The processionary caterpillar is an insect of the Lepidoptera family that, currently, is a true pest that mainly affects two tree species: pine and oak. With the arrival of spring and as temperatures rise, the caterpillars, which have remained in the form of larvae during the winter in their nests, easily visible in the treetops, as whitish ‘tangles', come down to the ground and it is easy to see impressive rows of these insects advancing. The processionary caterpillar bite is dangerous, both for people and animals. It is important to try to avoid any contact with these insects, as well as to know how to identify the processionary caterpillar bite and know what to do in such a case.

Processionary caterpillar bite symptoms and what to do

So, if you are interested, do not hesitate to continue reading this article of and know what are the symptoms of the bite of the processionary caterpillar and what to do in this case.

Why Processionary Caterpillar Bites Are Dangerous

Experts point out that the proliferation of processionaries, which each year generates a multitude of more or less serious incidents, is another of the appreciable consequences of climate change. In Spain, every year its presence becomes evident not only in wooded areas, but also in parks, gardens and in any small pine forest. Not only in Spain, but also in many other regions of the world the processionary caterpillar is already considered a pest that must be reduced due to the danger involved in its bite.

In the first place, these insects cause a serious defoliation in the tree they inhabit, devouring its leaves until causing severe damage. When they begin their descent through the trunk of the tree to look for a place underground, it is the most dangerous phase for humans (especially children) and also for other animals, such as dogs when we walk with them through these areas.

Processionary caterpillars have their body covered with tiny hairs, which are actually small spikes that the insect can detach not only at the slightest contact, but also when detecting any threat or danger situation. In the case of the pine processionary, those spike-like villi, which are called trichomes, contain a dangerous toxin, the thermolabile toxin called Thaumatopine, capable of triggering a strong and dangerous allergic reaction.

Symptoms of processionary caterpillar bite

From the end of winter, in the spring and during the first weeks of summer, extreme caution must be exercised in areas of pine forests before the possibility of being near a colony of caterpillars or being in the passage of a dangerous ‘train' of those who come to form these insects, since, the caterpillars advance in a row, attached to each other and confused with the color of the earth itself. The allergic reaction to contact with the processionary caterpillar and its trichomes is almost immediate and the first symptom is an intense itching in the affected area. More than itching, it is almost a difficult burning to calm, which is usually accompanied by a rash.

Contact with the toxin triggers a massive release of histamine in the body, something that implies other manifestations, especially irritation of the eyes and inflammation of those areas where the toxin has acted, for example, inflammation of the eyelids, nose, or tongue in the case of a small child or a pet that has smelled, touched and perhaps nibbled directly on the row of caterpillars or a branch they just passed.

The sensation of skin burning in the affected area is unmistakable and if, in addition, the tiny hairs have been inhaled through the nose when breathing, severe complications can arise, such as breathing difficulties, inflammation of the nasal mucous membranes or even anaphylactic shock in people especially sensitive to the action of allergens that the caterpillar gives off. In these cases, urgent medical care is essential.

On a dermatological level, the processionary caterpillar bite involves not only a strong itching, but also pain in the area. Inflammation, which is usually accompanied, is especially dangerous in the case of pets because it could involve swelling of the tongue and the whole mouth, with a possible risk of severe respiratory distress.

What to do in case of processionary caterpillar bite

Being aware of the danger that can hide the shade of those beautiful and pleasant pines, as a first preventive measure it is convenient to remember the importance of carefully checking the area through which we walk or intend to make a break and verify that we are not in the passage area of processionary caterpillar.

Even so, if we notice any of the symptoms described, during a walk in the countryside or a posteriori, it is essential to act quickly to mitigate the effects of a possible processionary caterpillar bite, especially in the case of the smallest and animals, since it is easier for them to have the reaction in the face or even in the mouth. Some basic measures that must be implemented are:

  • Check the area where the hives manifest, in case there is any caterpillar that is still attached to any part of the body. In this case, never touch it directly with your hands (you would aggravate the problem and it would sting you too). Always try to remove it with tweezers or gloves.
  • It is important to remove any remaining toxin from the skin as soon as possible and you should do it only by washing the area with plenty of water, without rubbing and without applying soaps or any other hygiene product.
  • Although it is not easy, you have to try to avoid scratching so as not to worsen the situation.
  • If the symptoms persist, you can consult with the pharmacist to acquire a moisturizing and soothing cream that relieves the symptoms.
  • In severe cases of inflamed areas, breathing difficulties, sudden fever or any other anomalous symptom, it is essential to go to hospital emergencies.

Now that you know all this about the symptoms of the processionary caterpillar bite and what to do about it, we recommend you also read these other articles about What to do if your dog is bitten by a processionary caterpillar and how to eliminate processionary caterpillars.


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