Envenomation by the Mexican beaded lizard: a case report.

BACKGROUND: Envenomations by venomous lizards are rare. A single report of envenomation by a Mexican beaded lizard (Heloderma horridum) has been published. Further, anaphylaxis secondary to lizard envenomation has only been reported with the Gila monster. We report an envenomation that resulted in both systemic toxicity and anaphylaxis.

CASE REPORT: A 40-year-old male was bitten on his hand by a captive Mexican beaded lizard. The patient experienced severe local pain, dizziness, vomiting, and diaphoresis. Upon arrival to the hospital, he was lethargic, vomiting, and in severe pain with marked swelling of his hand, lips, and tongue. His blood pressure was 110/63 mm/Hg with a pulse of 60 beats/minute. The patient's oxygen saturation decreased to 55%, and he required oxygen, although cyanosis was not observed. He was treated with normal saline, diphenhydramine, methylprednisolone, famotidine, ondansetron, morphine, and hydromorphone. The patient was admitted to intensive care where he continued to complain of severe pain requiring morphine. Local X-ray revealed only soft tissue swelling. Remarkable initial laboratory values included WBC 18,500 k/mm3 with 80% segs. Over the next eight hours, the patient's symptoms gradually improved. He had persistent local swelling at the bite site along with erythematous streaking up the forearm. He had an uneventful hospital course until his eventual discharge the following day.

CONCLUSION: Significant envenomations by members of the Helodermatidae family are rare. Systemic toxicity usually resolves within one to two days with supportive care. Prior envenomations may predispose patients to anaphylactic reactions.