Envenomation by the Mexican beaded lizard: a case report

Area of Science:

• Herpetology
• Toxicology
• Emergency Medicine

Background:

• Envenomations by venomous lizards, particularly the Mexican beaded lizard (Heloderma horridum), are infrequently documented.
• Anaphylaxis following lizard envenomation has been primarily associated with the Gila monster, not the Mexican beaded lizard.
• This case highlights a rare instance of combined systemic toxicity and anaphylaxis from Mexican beaded lizard envenomation.

Observation:

• A 40-year-old male presented with severe local pain, swelling, dizziness, vomiting, and diaphoresis after a Mexican beaded lizard bite.
• The patient experienced significant systemic effects including lethargy, severe pain, and a critical drop in oxygen saturation to 55%, requiring intensive care.
• Initial laboratory findings revealed an elevated white blood cell count (18,500 k/mm3) with 80% neutrophils, indicative of a significant inflammatory response.

Findings:

• The patient received supportive care, including intravenous fluids and medications for pain and allergic reactions (diphenhydramine, methylprednisolone, famotidine).
• Symptoms gradually improved over eight hours, with discharge the following day, though local swelling and erythema persisted.
• The case demonstrates that Mexican beaded lizard envenomation can lead to severe systemic toxicity and anaphylaxis.

Implications:

• Significant envenomations by Helodermatidae family members, though rare, necessitate prompt medical evaluation and supportive care.
• Systemic toxicity from these envenomations typically resolves within 48 hours with appropriate management.
• Individuals with prior envenomation history may be at an increased risk for developing anaphylactic reactions upon subsequent exposure.