Green Iguana Health Problems: Causes, Signs, and Prevention

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Green iguanas develop a fairly predictable set of iguana health problems. Almost all of them start in the enclosure rather than with the animal itself. Get the temperature, UVB, or diet wrong for long enough, and it will show.

This guide covers the conditions owners run into most. It explains what causes each one and the signs to watch for. It also covers when a problem needs a reptile veterinarian rather than home care.

For the baseline setup that prevents most of this, see our green iguana care guide, enclosure guide, and heating and lighting guide.

Metabolic bone disease

Metabolic bone disease, usually shortened to MBD, is the biggest health risk facing pet iguanas. It develops when an iguana cannot process calcium properly. UVB exposure that is too weak or dietary calcium that is too low can both cause it, and so can a skewed calcium to phosphorus ratio.

Early signs include a softened lower jaw and swollen or knobby limbs. An affected iguana often grows reluctant to move or climb, and VCA lists muscle twitching and seizures in advanced cases. As the disease progresses, bones can bend or fracture under the animal’s own weight.

Treatment is veterinary, not home based. VCA describes injectable or oral calcium, vitamin supplements, and sometimes calcitonin, followed by permanent changes to lighting and diet. Bone deformities that have already formed do not reverse.

Prevention rests on three things working together. UVB bulbs in the 290 to 320 nanometer range should sit within about 12 inches of the animal. They should also get replaced roughly every six months as output fades.

Diet should hold a minimum 2 to 1 calcium to phosphorus ratio. That gets backed up with regular calcium dusting on food. See our heating and lighting guide for bulb placement and our diet guide for supplement schedules.

Shedding problems (dysecdysis)

Iguana shedding is a normal, ongoing process rather than a single event. Young, fast growing iguanas shed in patches every 4 to 6 weeks. Adults shed about once a year as growth slows.

A healthy iguana sheds its skin in flakes and strips. It often looks dull or grayish just before a shed starts and glossier once the shed finishes. That is simply how iguanas shed their skin.

Problems arise when a shed gets stuck, most commonly around the toes, tail tip, or dewlap. Retained skin there can act like a tourniquet and cut off circulation. Low humidity is the usual trigger, since skin needs enough moisture to separate cleanly from the new layer underneath.

Our humidity guide covers the ranges that keep sheds coming off in one piece.

A shed that will not budge after a few days of misting and soaking needs help. So does any retained skin wrapped tightly around a toe or the tail.

Gentle soaking in shallow water at 77 to 85°F softens the skin. The MSD Veterinary Manual describes soaks of several hours for a badly retained shed, after which damp gauze can work the skin free. It also lists parasites, poor nutrition, and a lack of rough surfaces to rub against as causes beyond low humidity.

Never peel or pull a stuck shed dry. Handling should also be minimized during active shedding, since the new skin underneath is more sensitive than usual. For general background on lizard shedding across species, see our lizard shedding guide.

Mouth rot (infectious stomatitis)

Mouth rot is a bacterial infection of the mouth tissue. The earliest sign is tiny purplish red spots inside the mouth, followed by redness, swelling, or a cheesy discharge along the gum line, sometimes with visible pus pockets. It often follows an injury from a fall, a fight, or a strike against enclosure furniture.

An iguana with mouth rot may stop eating, drool more than usual, or paw at its own mouth. The infection can spread into the jawbone if it is ignored. Any of these signs warrants a veterinary exam rather than a wait and see approach.

Treatment typically involves removing dead tissue, antiseptic cleaning, and a course of antibiotics prescribed by a vet. Catching mouth rot early, before it reaches the bone, makes treatment far more likely to succeed.

Respiratory infections

A cold enclosure is the usual trigger for a respiratory infection, with stress, poor feeding, and dirty conditions adding to the risk. Nights that fall below 65 to 70°F leave an iguana’s immune system unable to keep up. Damp air without ventilation makes it worse.

VCA lists sneezing, discharge from the nose or eyes, bubbles at the mouth, rapid breathing, and lethargy as the signs. Do not confuse the ordinary sneezing of salt from the nostrils, which is how iguanas shed excess salt, with the mucus of an infection. Salt dries as white crust; infection discharge stays wet.

Diagnosis may involve X rays, blood tests, and cultures, and treatment is a course of oral or injectable antibiotics. Severe cases are hospitalized. Correcting the temperature and humidity at home is essential, or the infection returns.

Parasites and digestive upset

Internal parasites, mainly protozoa and intestinal worms such as pinworms, roundworms, and hookworms, are common in captive reptiles, and stress makes captive animals more susceptible. That is why annual fecal testing is standard practice. Most parasite loads produce no obvious signs at low levels, which is why testing beats watching for symptoms.

Heavier infestations can cause weight loss despite normal eating. Soft or foul smelling stool, lethargy, and a distended abdomen are other signs. Wild hatchling iguanas actually eat adult feces to seed their gut with beneficial microflora.

A captive juvenile’s digestive system depends on that same microbial community getting established early. A vet can run a fecal float or smear at the annual exam. A dewormer follows if parasites turn up.

Kidney (renal) disease

Adult iguanas are strict herbivores. Diets that include animal protein, such as dog food, monkey biscuits, or insects fed as treats, are linked to kidney disease over time. Older care advice sometimes recommended protein for growing iguanas.

Current veterinary guidance avoids animal protein at every life stage because of this risk.

Kidney disease develops slowly and often has no obvious early signs. Diet is the main lever an owner actually controls. Chronic dehydration and low humidity add further strain, so a soaking routine and adequate humidity matter alongside diet.

Too much vitamin D does damage of its own. VCA notes that over supplementing, or feeding dog or cat food, causes hypervitaminosis D, which brings appetite loss, lethargy, and kidney damage. Use a calcium powder without D3, such as Zoo Med Repti Calcium without D3, whenever UVB lighting is adequate, and keep the multivitamin to the schedule on the label.

Advanced signs include lethargy, appetite loss, and swelling. Bloodwork typically shows high phosphorus and low calcium, and the MSD Veterinary Manual notes that treatment options are limited once kidney damage is established. At that point, bloodwork from a reptile vet is the only way to confirm what is happening internally.

Egg binding (dystocia) in females

Female iguanas can develop and lay eggs with or without a male present. Egg binding, or dystocia, happens when a female cannot pass her eggs normally. It is a genuine emergency, not something to monitor for a few days.

Warning signs include a gravid female that goes past the expected laying window without laying. Straining, lethargy, appetite loss, and a firm swollen abdomen are all red flags. A proper nesting site with loose, diggable substrate helps prevent binding caused by nowhere suitable to dig.

Any suspected egg binding needs a same day veterinary exam, since untreated cases can be fatal. See our breeding guide and male vs female guide for more on reproductive behavior.

Burns and injuries

Unshielded heat bulbs, heat rocks, and basking spots without a safe gradient are a leading cause of burns. An iguana will happily press against a hot surface without moving away in time. Burns show up as blistered, blackened, or peeling skin, most often on the belly, feet, or tail.

Falls from high perches and tail injuries from enclosure doors round out the common injuries. So do bite or scratch wounds from mishandling an adult. Adult iguanas are strong enough to cause real damage with a tail strike or bite.

Their strength should never be underestimated during handling or cleaning. Any burn, open wound, or suspected fracture should go to a reptile vet rather than being treated with home remedies. Reptile skin heals slowly, and a wound that looks minor can turn into an abscess.

Abscesses are firm, pus filled swellings that follow bite wounds, bacterial infection, or dirty conditions. Small ones are removed surgically, and larger ones are opened, drained, and treated with antibiotics. Veterinary references also list foreign body ingestion and bladder stones among the conditions seen in pet iguanas, which is one more reason to keep loose substrate out of the food.

General warning signs across most iguana health problems

Several signs show up across nearly every condition on this list, which makes them worth knowing on their own. A healthy iguana is alert, moves with confidence, and basks readily under its heat lamp. A sick one often does the opposite.

Watch for a sudden drop in appetite, unusual lethargy, hiding more than normal, or a change in the color or firmness of droppings. Weight loss that is not tied to a normal seasonal slowdown is also worth tracking. Our behavior guide covers what normal activity looks like, which makes it easier to notice when something is off.

None of these signs points to one specific disease on its own. Together with the more targeted symptoms described above, they help narrow down what is actually going wrong.

Do iguanas carry diseases that affect people?

Yes. Like most reptiles, iguanas can carry Salmonella on their skin and in their droppings without showing signs of illness themselves.

The standard precaution is washing hands before and after handling the iguana or its enclosure. Keep the animal and its supplies away from kitchen food surfaces too.

When to see a reptile veterinarian

An annual exam with a reptile veterinarian catches most iguana health problems early. It should include a physical check and fecal parasite testing. Between visits, a few signs should trigger a call regardless of the calendar.

These include not eating for more than a few days, a soft or swollen jaw, and retained shed that will not release. Discharge around the mouth, straining, a distended abdomen in a female, and any burn, wound, or limping are also worth a call.

Reptile veterinary care is a specialized field. It is worth finding an exotics focused vet before a problem happens rather than searching during an emergency.

Costs for exams, bloodwork, and treatment add to the overall investment of iguana ownership. Our cost of ownership guide covers what to budget for. Building that cost into the plan from the start keeps small problems from turning into large, expensive ones.

Frequently Asked Questions

What is the most common health problem in pet iguanas?

Metabolic bone disease is the most common and most serious iguana health problem. It is caused by insufficient UVB or dietary calcium. Correct lighting and a calcium rich diet from the start largely prevent it.

Do iguanas shed their skin?

Yes, iguanas shed in patches throughout life. Young iguanas shed every 4 to 6 weeks, and adults about once a year. Adequate humidity and regular soaking help sheds come off cleanly.

What diseases do iguanas carry that can affect humans?

Iguanas can carry Salmonella on their skin and in their droppings without appearing sick. Washing hands after handling the animal or its enclosure is the main precaution owners should take.

How do I know if my iguana has metabolic bone disease?

Early signs include a soft or rubbery lower jaw, swollen limbs, and reluctance to move. Any of these signs calls for an exam with a reptile veterinarian rather than waiting to see if it worsens.

Why is my iguana’s shed getting stuck?

Stuck shed almost always points to low humidity, which stops the old skin from separating cleanly from the new layer. Retained skin around the toes or tail should be soaked and gently worked free, since it can cut off circulation.

How often should an iguana see a vet?

A healthy adult iguana should see a reptile veterinarian at least once a year for a physical exam and fecal parasite testing. Any sudden change in appetite, mobility, or appearance warrants a visit outside that schedule.