D – Transparent tape application and removal over the area of dermatitis
While most caterpillars of the order Lepidoptera in the US are not dangerous to humans, some have evolved defense mechanisms including venoms administered by the urticating hairs or spines. Humans who contact these caterpillars may develop dermatitis, itching, erythema, and rarely systemic effects. Erucism refers to cutaneous dermatitis from contact with caterpillar hairs and spines, while lepitopterism refers to the systemic adverse effects. Initial treatment includes the removal of embedded hairs or spines using tape such as transparent tape [1,2,3]. The photograph contains an example of one such specimen, the buck moth caterpillar Hemileuca maia.
In 2018, US Poison Control Centers received 2,816 cases of caterpillar exposures, with over 40% occurring in people 19 years old or younger and children 5 years or younger accounting for 20% of all cases . Seasonal epidemics have been reported .
What is the clinical presentation of erucism [1, 2, 3, 6]?
The presentation depends on the caterpillar species.
In the United States, most native venomous caterpillars contain histamine-like toxins or stimulate the release of endogenous histamine.
Dermatitis, welts, itching, and burning sensation are common.
Systemic effects are rare in caterpillars native to the United States but may include generalized urticaria, headache, conjunctivitis, vomiting, bronchospasm, dizziness, diaphoresis, and abdominal pain.
South American caterpillars of Lonomia moths produce a toxin that can result in “hemorrhagic syndrome”, which may manifest as consumptive coagulopathy and renal failure.
How do you manage erucism [1, 2, 3, 6]?
Place transparent tape over the affected area to remove embedded hairs or spines, using a new piece of tape each time.
Apply ice packs to reduce the burning sensation; isopropyl alcohol wipes may also enhance cooling
Hydrocortisone cream and antihistamine cream may provide relief
Consider topical anesthetics, such as lidocaine 2-4% ointment, for pain relief
Provide local wound care and tetanus prophylaxis
Ocular lesions require extensive irrigation and ophthalmology follow up
Watch for anaphylactoid/anaphylactic symptoms and treat them appropriately
Caterpillar envenomations frequently present with dermatitis, itching, and burning at the site of exposure to hairs or spines.
Removal of the hairs or spines with tape is a key component of management.
Systemic symptoms are rare in most species native to the United States.
Local pain relief is accomplished with ice packs and topical anesthetics, hydrocortisone cream, and/or antihistamine cream.
This post has been peer-reviewed on behalf of ACMT by Bryan Judge, Louise Kao, and Daniel Repplinger
Hossler EW. Caterpillars and moths: Part I. Dermatologic manifestations of encounters with Lepidoptera. J Am Acad Dermatol. 2010 Jan;62(1):1-10; quiz 11-2. Review. Erratum in: J Am Acad Dermatol. 2010 Apr;62(4):666. PMID: 20082886
Hossler EW. Caterpillars and moths: Part II. Dermatologic manifestations of encounters with Lepidoptera. J Am Acad Dermatol. 2010 Jan;62(1):13-28; quiz 29-30. Review. Erratum in: J Am Acad Dermatol; 62(4):666. PMID: 20082887
Repplinger DJ & Hahn IH. Arthropods. In: Goldfrank’s Toxicologic Emergencies, Nelson LW Howland MA Lewin NA eds; 11th< edition 2019; McGraw Hill, New York, NY.
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Walker RB, Thomas T, Cupit D, Giaquinto-Shreves J. An epidemic of caterpillar sting dermatitis in a rural West Virginia community. W V Med J. 1993 Feb;89(2):58-60. PMID: 8442349
Schmitberger PA, Fernandes TC, Santos RC, de Assis RC, Gomes AP, Siqueira PK, Vitorino RR, de Mendonça EG, de Almeida Oliveira MG, Siqueira-Batista R. Probable chronic renal failure caused by Lonomia caterpillar envenomation. J Venom Anim Toxins Incl Trop Dis. 2013 Jun 3;19(1):14. PMID: 23849585