Management of severe pain after dermal contact with caterpillars (erucism): a prospective case series

Abstract

Context: Erucism, envenomation caused by dermal contact with larval forms of moths, may result in intense local pain, mainly after contact with puss caterpillars (family Megalopygidae).

Objective: To evaluate the response to different treatments for controlling severe pain in a case series of erucism in Campinas, southeastern Brazil.

Patients and methods: Prospective cohort study. A Numeric Pain Rating Scale (NPRS 0–10) was used to assess pain intensity in the Emergency Department (ED). Pain was considered as severe upon ED admission (T0) when the NPRS was ≥8. Inclusion criteria: age ≥8 years old, severe pain at T0, with continuous assessment of pain intensity in all patients using the NPRS during the ED stay (T5, T15, T30, T60 min and at discharge).

Results: Fifty-five patients fulfilled the inclusion criteria and were divided into three groups according to the initial treatment at T0: local anesthesia alone with 2% lidocaine (group 1, n = 15), local anesthesia and analgesics (group 2, n = 26) and analgesics without local anesthesia (group 3, n = 14). Most patients were admitted within 2 h after dermal contact with the stinging bristles of caterpillars (median =90 min, IQR: 40–125 min). In 22 cases (40%), the caterpillar was brought for identification (Podalia spp., n = 18; Megalopyge spp., n = 4). There was a significant decrease in pain from T5 onwards with all of the treatments. When the short-term response (T5 and T15) was considered, analgesia was more effective in groups 1 and 2 compared to group 3 (p < .01). Additional analgesia (from T5 until discharge) was frequently required (n = 25/55), mainly in group 1 (n = 11/15). The median length of stay in the ED was 120 min (IQR: 80–173 min).

Conclusions: The association of local anesthesia with analgesics was apparently a good combination for the rapid management of severe pain in the ED.

Keywords:

• Analgesia
• erucism
• Megalopygidae
• Numeric Pain Rating Scale
• Podalia spp
• severe pain

Disclosure statement

No potential conflict of interest was reported by the author(s).