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.