Metabolic bone disease of the frilled lizard
Metabolic bone disease is a very common disorder in captive-bred reptiles, including the frilled lizard. \nIt results from an imbalance between calcium, phosphorus and vitamin D3. \nThis imbalance weakens the animal's skeleton, which become...
What is it?
Metabolic bone disease is a very common disorder in captive-bred reptiles, including the frilled lizard. \nIt results from an imbalance between calcium, phosphorus and vitamin D3. \nThis imbalance weakens the animal's skeleton, which becomes soft, deformed or brittle. \nThis is one of the main causes of veterinary consultation in reptiles that are inadequately fed or lit.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
The first signs are often discreet: the animal moves less, eats less well, seems tired. \nWith evolution, the legs can become deformed or swollen, the jaw becomes soft or asymmetrical (sometimes called “rubber jaw”). \nThe animal may limp, have difficulty climbing onto a branch, or exhibit tremors and muscle spasms. \nIn advanced forms, spontaneous fractures, paralysis of the hind legs or convulsions may appear. \nThe spine may also curve abnormally.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The main cause is a lack of calcium in the diet, often aggravated by an excess of phosphorus (too fatty or unbalanced prey). \nA lack of exposure to UVB rays, essential for the synthesis of vitamin D3 in the skin, prevents the lizard from properly absorbing calcium even if it receives it in its food. \nThe lizard's body then compensates by drawing calcium from its own bones, which gradually weakens them.
Young, growing lizards are particularly vulnerable because their calcium requirements are high. \nReptiles fed only non-supplemented insects (crickets, worms) without calcium powder are at risk. \nA terrarium without suitable UVB lighting, or with UVB bulbs that are too old (UV emission decreases over time without the visible light changing), is a major factor. \nA pregnant or laying female has increased calcium needs and can develop the disease more quickly.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian examines the animal, palpates the bones and jaw to assess their abnormal flexibility. \nX-rays make it possible to visualize reduced bone density and to look for fractures or deformities. \nA blood test may be suggested to measure calcium and phosphorus levels, even if these values sometimes remain normal in the event of compensation by the body. \nThe food history and lighting conditions of the terrarium are systematically reviewed.
Treatment
Management is based on correcting diet and UVB lighting, combined with calcium and vitamin D3 supplementation under veterinary supervision. \nIn some cases, injectable calcium supplementation may be used clinically for severe forms. \nStrict rest and layout of the terrarium (limit heights, soft surfaces) are recommended during bone consolidation. \nPainkillers may be prescribed for the comfort of the animal.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Provide a varied diet with regular calcium supplementation (powder sprinkled on prey) according to the recommendations of the veterinarian specializing in reptiles. \nInstall UVB lighting adapted to the species, positioned at the right distance, and replace it regularly even if it still works visually. \nEnsure a correct temperature gradient in the terrarium to allow good digestion and normal metabolism. \nHave young growing lizards monitored by a veterinarian for preventive control.
Possible complications
Without treatment, the disease can progress to multiple fractures, permanent paralysis of the limbs, or even death. \nSevere hypocalcemia can cause seizures or cardiac arrest. \nEstablished bone deformities (jaw, spine) may remain irreversible even after stabilization.
When to see a veterinarian
The animal limps or has difficulty moving normally
The jaw appears soft, misshapen or asymmetrical
Tremors, spasms or convulsions are observed
The animal no longer eats or remains abnormally prostrate
A leg or tail appears swollen, deformed or broken
The lizard can no longer get up on its own
Prognosis
The prognosis is good if the disease is detected early and diet and lighting are corrected quickly. \nIn advanced forms with fractures or paralysis, recovery is more uncertain and after-effects may persist. \nRegular veterinary follow-up clearly improves the chances of complete recovery.
Frequently asked questions
Can my frilled lizard fully recover?
Yes, if the disease is detected at an early stage and diet and UVB lighting are corrected quickly under veterinary supervision. In advanced forms, bone sequelae may persist.
Is a regular UVB lamp enough?
No, you need a UVB lamp specific to reptiles, adapted to the species, positioned at the right distance and replaced regularly even if it still illuminates normally, because its UV emission decreases over time.
Can I give calcium without veterinary advice?
Basic calcium supplementation is part of routine care, but in the event of signs of illness, it is important to consult a veterinarian before any additional supplementation, particularly vitamin D3, to avoid excess.
How do I know if my lizard is getting enough UVB?
A veterinarian specializing in reptiles can evaluate the installation of the terrarium and the health of the animal. It is also recommended to check the date of manufacture of the bulb and follow the manufacturer's instructions for replacement.
References
AVMA — American Veterinary Medical Association
Content reviewed by the TunisieVet editorial team · Updated 28 September 2026
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