Medscape is available in 5 Language Editions – Choose your Edition here.


Caterpillar Envenomation Treatment & Management

  • Author: Robert L Norris, MD; Chief Editor: Scott H Plantz, MD, FAAEM  more...
Updated: Jul 19, 2016

Prehospital Care

The involved skin should be immediately washed with soap and water, and dried without contacting the skin (eg, use a hair dryer).

Local cooling measures can be applied to reduce pain. This may be enhanced by applying topical isopropyl alcohol or ammonia.

Following ocular exposure, the eyes should be irrigated immediately with copious water.

Following dermal exposure to irritant or toxic hairs or setae of caterpillars or moths, sticky tape (especially duct tape) can be applied to the site in an effort to remove retained setae. Alternative effective methods of removal include use of rubber cement, clear fingernail polish, or facial peels (each applied, allowed to dry, then peeled away).

If acute symptoms follow respiratory exposure, supportive care is in order as necessary, including oxygen, antihistamines, and beta-agonist inhalers, if available.

Anaphylaxis should be treated in standard fashion.

Following caterpillar stings, the extremity should be splinted and elevated, and ice should be applied to reduce pain.

Any potentially constrictive jewelry should be removed before swelling progresses.


Emergency Department Care

Wash the skin with soap and water as mentioned above if this has not already been done in the field.

Ensure appropriate tetanus immunization status.

Treat skin exposure as follows:

  • Apply sticky adhesive tape (especially duct tape) to the site to remove all remaining hairs or spines possible. Other measures of removal as described previously for prehospital care can also be tried.
  • Acute dermatitis can be treated with antihistamines (H1 and/or H2 blockers), although their efficacy is controversial. Additionally, topical steroids may be employed. Systemic steroids may be necessary in patients with severe or persistent cutaneous symptoms. Application of antipruritic products containing menthol may be soothing.
  • Prostaglandin-synthetase inhibitors, such as aspirin or indomethacin, have been reported to reduce associated discomfort, but should be avoided if any evidence of coagulopathy is present.

Treat respiratory exposure as follows:

  • Symptoms can be managed with antihistamines (H1 and/or H2 blockers) and beta agonist aerosols/inhalers if wheezing is present.
  • If significant symptoms occur, supplemental oxygen administration may be needed, and systemic steroids may be useful.

Treat ocular exposure as follows:

  • Instill a topical anesthetic and irrigate the eyes immediately with copious saline.
  • Perform a slit lamp examination with fluorescein. The patient should receive close ophthalmologic follow-up care to rule out retained setae or hairs.
  • Eye complications resulting from a retained migrating hair can be severe, and surgical removal may be necessary.

Treat stings as follows:

  • Management is primarily symptomatic and supportive. Splint and elevate the involved extremity; ice can be applied to reduce pain and swelling. Efforts, as outlined above, should be instituted to remove any retained spines or hairs.
  • Narcotic analgesics may be required for pain relief. Anecdotal reports exist of the successful use of calcium gluconate (eg, 10 mL of a 10% solution by slow intravenous [IV] administration) to relieve muscle pain following M opercularis stings. Antihistamines (H1 and/or H2 blockers) may reduce concomitant pruritus.

Treat rare cases of caterpillar or moth-related anaphylaxis in standard, aggressive fashion, including airway management, epinephrine, oxygen, antihistamines, steroids, IV fluids, and vasopressors as needed.



Consultations usually are not necessary following most caterpillar contacts. An ophthalmologist should be promptly consulted if ocular involvement is present.[13]



All caterpillars should be considered potentially toxic, and contact should be avoided. Children particularly should be warned in this regard. When working outdoors during peak caterpillar seasons, individuals should wear long-sleeved shirts, long pants with the cuffs tucked into their socks, and work gloves. Collars should be close fitting to avoid having a caterpillar fall into one's shirt. A broad-brimmed hat may prevent caterpillars from falling from an overhead tree onto one's head and face. When working in an area where airborne caterpillar debris is a problem, a tight-fitting face mask and eye protection should be used. Laundered clothing should not be hung outdoors to dry as it may collect airborne caterpillar debris.

Insecticides can be used to control caterpillar populations. A professional pest specialist or entomologist should be consulted before applying such agents because many caterpillar species are beneficial to agricultural and ornamental plants.

If a caterpillar is found on one's body, it should be gently lifted off with a stick to avoid contact with potentially toxic hairs, setae, or hemolymph.


Long-Term Monitoring

Victims of caterpillar stings can be observed for 2 hours in the ED to ensure that they do not develop significant systemic toxicity.

Although uncommon, secondary infection can occur following erucism or lepidopterism. Instruct patients to follow up immediately if any signs or symptoms of infection occur. Patients with particularly severe exposures should have scheduled follow-up care to exclude infection or necrosis.

All patients with ocular exposures to caterpillar or moth hairs or setae should receive early ophthalmologic follow-up care to exclude retained fragments, which can lead to catastrophic complications.

Following caterpillar stings, local findings, including pain, may persist for several days. Systemic symptoms usually resolve in 24 hours.

Patients who experience a significant allergic reaction to caterpillar exposure (eg, hypotension, bronchospasm) should receive a prescription for an epinephrine self-administration device prior to discharge from the hospital and should be instructed in its use. They also should consider obtaining and carrying medical alert identification of this history. Unlike therapy for hymenoptera-induced anaphylaxis, there is no desensitization therapy for patients highly allergic to caterpillars.

Contributor Information and Disclosures

Robert L Norris, MD Professor, Department of Emergency Medicine, Stanford University Medical Center

Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, International Society of Toxinology, American Medical Association, California Medical Association, Wilderness Medical Society

Disclosure: Nothing to disclose.

Specialty Editor Board

John T VanDeVoort, PharmD Regional Director of Pharmacy, Sacred Heart and St Joseph's Hospitals

John T VanDeVoort, PharmD is a member of the following medical societies: American Society of Health-System Pharmacists

Disclosure: Nothing to disclose.

Gino A Farina, MD, FACEP, FAAEM Professor of Emergency Medicine, Hofstra North Shore-LIJ School of Medicine at Hofstra University; Program Director, Department of Emergency Medicine, Long Island Jewish Medical Center

Gino A Farina, MD, FACEP, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Scott H Plantz, MD, FAAEM Associate Clinical Professor of Emergency Medicine, Department of Emergency Medicine, University of Louisville School of Medicine

Scott H Plantz, MD, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Samuel M Keim, MD, MS Professor and Chair, Department of Emergency Medicine, University of Arizona College of Medicine

Samuel M Keim, MD, MS is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Public Health Association, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

  1. Bonamonte D, Foti C, Vestita M, Angelini G. Skin Reactions to pine processionary caterpillar Thaumetopoea pityocampa Schiff. ScientificWorldJournal. 2013. 2013:867431. [Medline].

  2. Iacobucci G. Oak moth caterpillar that causes rash is spreading in southeast England. BMJ. 2013 May 8. 346:f2964. [Medline].

  3. Wills PJ, Anjana M, Nitin M, Varun R, Sachidanandan P, Jacob TM, et al. Population Explosions of Tiger Moth Lead to Lepidopterism Mimicking Infectious Fever Outbreaks. PLoS One. 2016. 11 (4):e0152787. [Medline].

  4. DuGar B, Sterbank J, Tcheurekdjian H, Hostoffer R. Beware of the caterpillar: Anaphylaxis to the spotted tussock moth caterpillar, Lophocampa maculata. Allergy Rhinol (Providence). 2014 Jul. 5 (2):113-5. [Medline].

  5. Bleriot A, Couret C, Lebranchu P, Le Meur G, Weber M. [Keratitis due to foreign bodies from a processionary caterpillar nest]. J Fr Ophtalmol. 2015 Jan. 38 (1):85-6. [Medline].

  6. Prasad SC, Korah S. Rare Presentation of Ophthalmia Nodosa. Middle East Afr J Ophthalmol. 2015 Oct-Dec. 22 (4):520-1. [Medline].

  7. Casado Verrier E, Carro Rodríguez MA, de la Parte Cancho M, Piñeiro Pérez R. [Systemic reaction after pine processionary caterpillar ingestion. Conservative management?]. Arch Argent Pediatr. 2016 Jun 1. 114 (3):e151-4. [Medline].

  8. MacKinnon JA, Waterman G, Piastro K, Oakes J, Pauze D. Oropharyngeal Edema in an 8-Month-Old Girl after Woolly Bear Caterpillar Exposure. J Emerg Med. 2015 Nov. 49 (5):e147-9. [Medline].

  9. Sánchez MN, Mignone Chagas MA, Casertano SA, Cavagnaro LE, Peichoto ME. [Accidents with caterpillar Lonomia obliqua (Walker, 1855). An emerging problem]. Medicina (B Aires). 2015. 75 (5):328-33. [Medline].

  10. Maggi S, Faulhaber GA. Lonomia obliqua Walker (Lepidoptera: Saturniidae): hemostasis implications. Rev Assoc Med Bras. 2015 May-Jun. 61 (3):263-8. [Medline].

  11. Medeiros DN, Torres HC, Troster EJ. Accident involving a 2-year-old child and Lonomia obliqua venom: clinical and coagulation abnormalities. Rev Bras Hematol Hemoter. 2014 Nov-Dec. 36 (6):445-7. [Medline].

  12. Schmitberger PA, Fernandes TC, Santos RC, de Assis RC, Gomes AP, Siqueira PK, et al. Probable chronic renal failure caused by Lonomia caterpillar envenomation. J Venom Anim Toxins Incl Trop Dis. 2013 Jun 3. 19 (1):14. [Medline].

  13. Lipkova B, Gajdosova E, Kacerik M, Duranova M, Izak MG. Caterpillar setae penetration in an eye: long-term follow-up. Retin Cases Brief Rep. 2013 Summer. 7 (3):252-4. [Medline].

  14. Hossler EW. Caterpillars and moths. Dermatol Ther. 2009 Jul-Aug. 22(4):353-66. [Medline].

Caterpillar envenomations. Puss caterpillar or asp. Photo courtesy of the Arizona Poison and Drug Information Center.
Distinguishing dangerous from harmless caterpillars can be difficult, and handling any caterpillar with bare skin should be avoided. These are harmless tomato hornworm caterpillars (larval form of the five-spotted hawk moth [Manduca quinquemaculata])
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.