Common Green Iguana Health Issues

Green iguana health problems trace back overwhelmingly to husbandry, and one condition in particular is common enough in this species that understanding it should shape every other decision you make about care.

Metabolic Bone Disease (MBD)

This is the defining health issue for pet iguanas: probably the most common medical problem in captive iguanas, and lizards are among the reptiles where it turns up most. Watch for a swollen or rubbery lower jaw, softening of the jaw and facial bones, swollen or bowed hind limbs, tremors, and an inability to lift the trunk while walking. The causes are low dietary calcium relative to phosphorus, too little vitamin D3, or inadequate UVB exposure, often all three. Always see a vet: advanced cases need immediate, long-term treatment, and correct UVB, calcium, and diet ratio from day one is the difference between a healthy iguana and a statistic.

Kidney Disease

Linked to husbandry failures: chronic dehydration from low humidity, too much animal protein in a diet that should be plant-based (leave out insects, dog or cat food, and eggs), and over-supplementing vitamin D, which can itself cause severe kidney damage. Hypervitaminosis D shows first as appetite loss and lethargy, easy to mistake for a cold enclosure. Bladder stones (cystic calculi) also sit on the list of common iguana problems. Always see a vet.

Yellow Fungus

A fungal skin disease caused by Nannizziopsis species, also called CANV. Juveniles under two years old are the usual patients. It shows as tan to yellow crusty lesions that can appear anywhere on the body. Treatment is several weeks of prescription antifungal medication, and some cases are still fatal. See a vet at the first crusty patch that is not a shed.

Mouth Rot and Respiratory Infection

Mouth rot (infectious stomatitis) is bacterial. Look for pinpoint bleeding on the gums, swollen gums, or thick mucus in the mouth that looks like cottage cheese. It can swell the jaw like MBD does, but on one side only. Respiratory infection shows as sneezing, discharge from the nose or eyes, bubbles in the mouth, and fast or shallow breathing. Both infections follow stress, poor nutrition, and temperatures or humidity kept out of range. See a vet for either; they need professional treatment, not home correction alone.

Parasites

Pinworms are the common internal parasite, and mites the usual external one, hiding under scales and in skin folds around the head and legs. Most pinworm infections show no signs at all, and others only cause weight loss or loose stool, which is why a fecal exam belongs in the first vet visit and every annual one after it. Until that first exam, a new iguana lives apart from any other reptile, set up as the reptile quarantine guide describes.

Egg Binding (Ovostasis)

A genuine reproductive emergency in females. Most pet reptiles seen for this are single females with no exposure to a male, so a lone female iguana is not exempt. A female can form up to 40 eggs at a time. Signs are loss of appetite, a swollen abdomen, and weight loss. Poor nutrition, weak or missing UVB, and no place to nest all leave the follicles stuck, so a mature female needs a sandy area to bury eggs in whether or not a male is present. When she cannot lay, the fix is surgery. This is always an emergency: get to a vet immediately if you suspect it.

Thermal Burns and Substrate Impaction

Manageable and entirely preventable. Pet reptiles are commonly burned by poorly protected heat sources, so burns come from heat sources positioned where the iguana can contact them directly, and impaction comes from swallowing substrate that is too fine while feeding.

The Husbandry Pattern Worth Remembering

Nearly everything on this list traces back to getting UVB, calcium, humidity, and diet right from the start. MBD, the most common and most serious issue here, is highly preventable. The same husbandry-driven pattern runs through the other big lizards, and the savannah monitor shows it with an insect and rodent diet in place of greens.

Sources & Further Reading