Two cases of lepidopterism caused by indoor exposure to moths

Lepidoptera is an order of insects that comprises moths and butterflies. Contact with the irritating hairs of the adult and larval stages of some Lepidoptera species can induce dermatitis. Most local or systemic reactions are attributable to contact with the larval stage (caterpillars), known as erucism¹, but adult moths may also cause reactions, referred to as lepidopterism. Reactions caused by Lepidoptera are probably under diagnosed and may produce diverse dermatological presentations^{2) (3}. Outbreaks of cutaneous, ophthalmologic, or systemic reactions occasionally occur owing to seasonal abundance and wind dispersion. Moths may also be attracted to artificial lighting and infest indoor environments². We present two epidemiologically unrelated cases of presumptive lepidopterism. A56-year-old woman (Figure A) and a 31-year-old man (Figure B) from Rio de Janeiro presented in June 2013 and August 2014, respectively, with an acute, mildly pruritic, papular rash localized to the cervical region. Both individuals reported never having had a similar reaction before, were unaware of its cause, and had no history of allergic or hypersensitivity reactions. On careful history taking, both patients reported having had recent (within two days) contact with moths while cleaning infested indoor areas. They were treated with topical corticosteroids and oral antihistamines. The moths were not available for entomological examination. The findings of these cases highlight that a high level of suspicion is necessary and a history of contact with moths or caterpillars should be actively sought when treating patients with acute, unexplained, localized dermatitis.

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• ¹
  Warrel DA. Injuries, envenoming, poisoning, and allergic reactions caused by animals. : Warrel DA, Cox TM, Firth JD, editors. Oxford Textbook of Medicine. 5th ed. Oxford: Oxford University Press; 2010. p. 1324-1360.
• ²
  Hossler EW. Caterpillars and moths: Part I. Dermatologic manifestations of encounters with Lepidoptera. J Am Acad Dermatol 2010; 62:1-10.
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  Hossler EW. Caterpillars and moths: Part II. Dermatologic manifestations of encounters with Lepidoptera. J Am Acad Dermatol 2010; 62:13-28.

Publication Dates

• Publication in this collection
  May-Jun 2016

History

• Received
  17 Oct 2015
• Accepted
  23 Nov 2015