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Bites from poisonous lizards, crocodiles and iguanas
Medical expert of the article
Last reviewed: 04.07.2025
Significant bites from other reptiles include bites from venomous lizards, alligators, crocodiles, and iguanas.
Venomous lizards include the Gila monster (Heloderma suspectum), found in the southwestern United States and Mexico, and the escorpion (H. horridum), found in Mexico. Their complex venom contains serotonin, arginine esterase, hyaluronidase, phospholipase A2, and one or more salivary kallikreins, but very little neurotoxic component or coagulopathy enzymes. Fatal bites are rare. During the bite, the venomous lizard firmly grasps the victim's limb, and the venom is chewed into the body. Symptoms include intense pain, swelling and edema, ecchymosis, lymphangitis, and enlarged lymph nodes. Systemic manifestations such as weakness, sweating, thirst, headache, and tinnitus may develop in moderate to severe cases. Cardiovascular collapse is rare. The clinical course is similar to that of mild to moderate envenomation by common rattlesnakes. On site, the lizard should be removed with forceps, by holding a flame to its chin, or by submerging it completely under water. Inpatient care is supportive and as for pit viper envenomation; there is no antidote. The wound should be probed with a small needle to detect tooth fragments and then treated. Prophylactic antibiotics are not usually recommended.
Alligators and crocodiles usually bite people who look after them in captivity, although this can happen in the wild. The bites are not poisonous, and there is a high incidence of specific soft tissue infections [Aeromonas], but they are generally considered a normal injury. Wounds are irrigated with antiseptics and sanitized. Subsequently, delayed primary wound closure is performed or the wound is left to heal by secondary intention. Clindamycin and co-trimoxazole [sulfamethoxazole + trimethoprim] (first-line drugs) or tetracycline are prescribed for prevention.
Iguana bites and claw wounds are becoming more common as more people keep iguanas as pets. The wounds are superficial and are treated locally. Soft tissue infection is uncommon, but if it occurs, salmonella may be present in the wound. Treatment is with fluoroquinolone antibiotics.
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