Envenomation by caterpillars (erucism): proposal for simple pain relief treatment.

Abstract

To the editorErucism is the name given to injuries caused by mothlarvae in humans. The lesions are provoked by caterpillarbristles filled with toxins that penetrate the skin [1-4]. Thebristles are hollow and when they enter the skin and break,toxins that contain thermolabile proteins, proteolytic en-zymes and histamine are released [2]. The shape of bristlesindicates the families of caterpillars mainly associated withinjuries: Megalopygidae (fine setae throughout the body)and Saturniidae (setae in smallpinetreeformat,seeFigure 1) [3]. The toxins cause immediate severe pain,erythema, edema and immediate lymphangitis (Figure 1).In later stages, there may be vesicles, bullae, erosions, pe-techiae, superficial skin necrosis, and ulcerations [4]. Somegenera (Lonomia, Periga) can cause severe hemorrhagicsyndromes, but most manifestations are limited to excruci-ating pain and mild to moderate local inflammation [1-4].Treatment for such injuries is based on cold watercompresses and oral analgesics (dipyrone is the rule, butthe use of potent analgesics, such as tramadol hydro-chloride may be required). When painkillers do notcontrol the pain, nerve anesthetic blockade (lidocaine4.0 mL for adults) may be employed [1-4]. Based on ourpast experience, we suggest using serial application oftopical commercial anesthetics with 0.25% lidocaine and0.25% prilocaine in order to greatly decrease or eliminatethe pain, these drugs take effect in about half an hourand last for several hours [1,4]. They are easy to apply,does not interfere with the approach adopted for thiskind of accident, and it is especially useful for childrenand patients whose lesion sites do not allow blockades.