More than 50 species of caterpillars in the United States are capable of inflicting a painful sting. Caterpillars, the adolescent forms of moths and butterflies, often have stinging fibers and hairs as a form of protection against predators; sometimes these also contain toxins as well as being penetrating when released.
The slightest brush can cause contact dermatitis, pain, and itching. Being actively attacked by a caterpillar and stung can be very painful, depending on the species. Luckily, this injury is usually not serious in most people, but the pain and itching should be treated promptly, and if you have any allergy problems, it is wise to pay careful attention to your reactions.
Understand the types of reactions that are possible with a caterpillar sting:
Caterpillar dermatitis: itchiness and contact dermatitis, blisters, weals(welts), small red bumps, pain.
Contact with the Asian Dendrolimus pini caterpillar can cause an itchy rash, and even lead to forms of arthritis (polyarthritis/polychondritis,chronic osteoarthritis).
Bleeding and renal failure can occur after contact with the South American Lonomia caterpillar. Contact with this caterpillar can be dangerous, even fatal, if you handle it in numbers (such as picking up vegetation where lots of them are found). It is located in Brazil and there is an antivenin.
Calm the recipient of the sting. It's easier and less stressful to treat a sting if you're calm. Moreover, venom tends to travel faster when a patient is moving about. Understand that most caterpillar stings in North America and Europe, while painful, are benign. Deaths from caterpillar stings are rare.
Remove the caterpillar if it is still on the body. Use forceps or tweezers, not bare hands.
Place Scotch tape, cellophane tape, or duct tape over the site of the sting. Strip off repeatedly. This will remove the spines, hairs, and toxins.
Commercial face peel can be used in place of tape.
Wash the injured area using soap and water. Remove all contaminated clothing and wash in hot water.
Apply an ice pack to the stinging area after washing it. When the stinging sensation has reduced (check after 15–20 minutes), apply a paste made from baking soda and water.
Apply a topical anesthetic, if you have access to some.
Over-the-counter pain relief, such as Tylenol® or Panadol®, can be helpful. Follow the instructions on the package.
Swelling can be minimized by elevating the area of the sting.
You can reapply the ice pack once every hour for 15–20 minutes for the following hours, if needed.
A wet cloth is a suitable substitute for an ice pack.
Monitor the sting. Watch for oozing, rash, swelling, or change in coloration; if symptoms don't improve, seek medical attention.
If the patient suffers from asthma, hayfever, or other allergies, or if allergic symptoms arise, see a doctor immediately.
Document the caterpillar that stung you. This may be important later, if you observe new or worse symptoms. If you don't have a camera on hand, quickly note down features - color, relative length, texture, approximate number and texture of spines. Caterpillars to be on the look out for include:
The puss caterpillar or asp (Megalopyge opercularis): This is considered to be the most dangerous caterpillar in the United States and Central America. This is the larval form of the flannel moth and its range is from Maryland to Mexico. The bigger the caterpillar, the worse its impact. They are usually found on various trees and shrubs, including elm, maple, hack berry, oak, sycamore, etc. You are most likely to encounter it from June to September. All patients will feel pain when stung by this caterpillar, while one in three patients will feel headaches, muscle spasms, breathing difficulties, and convulsions.
Stinging rose caterpillar: Often found on bushes and low tree branches of redbud, oak, hickory, bayberry, wild cherry and sycamore.
Saddleback caterpillar: Severe irritation follows a sting from this caterpillar. It is often found on deciduous trees (e.g., chestnut, cherry, oak, basswood, and plum) and sometimes on corn.
Euclea delphinii caterpillar: This caterpillar is often found on oak, beech, chestnut, willow, pear, bayberry, sour wood, wild cherry and other trees.
Buck moth caterpillar: Has poisonous spines. Found on oak and willow trees, usually spring to mid-summer.
Io moth caterpillar: Has poisonous spines. Found on many plants, including corn, roses, willow, linden, elm, oak, locust, apple, beech, ash, currant, and clover, usually spring to mid-summer.
Hag moth caterpillar: This caterpillar looks like a dried leaf. It is usually found on the lower branches of trees and shrubs, including oak, chestnut, dogwood, sassafras, and ash.
Spitfire caterpillar (Australia): This caterpillar can shoot a liquid as well as causing contact dermatitis if the hairs get into the skin and break off.
Don't touch or handle brightly colored or hairy caterpillars. These features are often indicators of the presence of a sting or poison.
Unless you are a trained professional, do not keep wild animals as pets. If you want to raise caterpillars into butterflies or moths, there are special websites and catalogs from which you can order eggs and equipment.
Note the geographic area in which you received the sting and keep pets and children away from it. Alert officials if there appears to be any unusual level of breeding.
Don't scratch your sting.
It is possible to have an allergic reaction to caterpillar stings, and some caterpillars have particularly potent venom. Watch for symptoms like swelling of face, throat or tongue, mouth discoloration, difficulty breathing, or a quick-spreading rash. These can indicate a serious reaction, and require immediate medical attention.
Anti-histaminic drugs are reportedly not helpful with caterpillar stings.
Never let pets or children play with unknown creatures, even something as small as a caterpillar. Teach children to avoid brightly colored and spiny caterpillars especially- showy colors and crests of hairs are often nature's code for poison.
Even caterpillars that don't sting can be harmful to your yard. Watch for white, cobwebby nests of caterpillars in trees; evergreen bagworms and Gypsy Moth caterpillars are parasitic and can kill trees.
Things You'll Need
Tape (duct tape, Scotch tape, cellophane tape) or a commercial face peel
Baking soda (bicarbonate of soda) and water paste
Ice pack, or frozen food (Anything cold or frozen should do)