Metabolic Bone Disease (Avitaminosis) in Lizards


Avitaminosis in lizards is an illness caused by long term or chronic vitamin deficiency. It can also be caused by a defect in metabolic conversion, leading to your lizard not receiving as much of certain vitamins as it needs. It is often caused by a lack of variety of healthy food in the diet and not just insufficient quantity.

Early Signs of Metabolic Bone Disease

Avitaminosis has some very serious symptoms and many are not immediately apparent. Probably the first that the owner will notice are skin changes. Depending on the animal, this can present as loss of colour, spots or cracks. The owner should watch out for any of these changes and should check for other, more serious and difficult to spot signs immediately. If the reptile is also presenting with shedding problems or eye problems, in particular if the eyes are cloudy (which may be connected with shedding issues) or there is swelling around the eyes, it should be taken to the vet immediately.

Vitamin Supplements

Food supplements should be given to any caged reptile and if these are not given, or are given in the incorrect dosage, metabolic bone disease can be the result. It is particularly important that calcium is given in the correct quantity, but a vitamin supplement made specifically for reptiles should be sufficient to prevent it. Finally, it is very important that full spectrum fluorescent light should be used in the enclosure; vitamin D in particular is present naturally in very few foods and so light with the full spectrum is vital to provide this vital vitamin.

Later Signs of Avitaminosis

If the early signs are missed for some reason, the animal may go on to present with other symptoms. The owner may notice that the lizard is not eating properly. This may be because teeth are becoming loose or may by this time have actually fallen out. The bones will soften; this may result in fractures and when a history of the lizard is taken by the vet, it may be the case that this is historical. This will suggest that the animal has been suffering from metabolic bone disease for some time. Late symptoms which indicate that the lizard has had vitamin deficiency for some time will be convulsions and paralysis. Animals who have reached this stage are unlikely to recover.

A Note of Caution: Vitamin Doses Should not be Exceeded

Once the dangers of Avitaminosis have been explained, it is only natural that the careful lizard will address the giving of supplements. Each vitamin has its own optimal dose and it is as easy to overdose as under. For example, an excess of vitamin D can result in calcification of arteries, with the same result in a lizard as in a human; heart failure. An excess of vitamin A can cause internal bleeding and resulting organ failure.

The Role of Calcium in Metabolic Bone Disease

Although most lizards presenting with Avitaminosis will be found to be lacking in vitamins across the spectrum, the most likely to cause this problem is, perhaps obviously, calcium. As the building block of bone, calcium is essential to maintain a healthy skeleton and teeth. But calcium is not just important in bone formation; it is also very necessary in many other bodily functions, for example clotting after a small injury, and so the body makes constant calls on the stores of calcium. If there is not enough in the diet, it will be leached out of the bones for use in other vital processes, leaving the lizard at risk of metabolic bone disease.

Lacking Calcium

If you are worried that your lizard may be lacking calcium, your first port of call should be the vet. It is important not to hugely increase any supplement or food you give to your lizard. As a species, lizards tolerate dietary change very badly and you can put it off feeding altogether for a while, which would be totally counter-productive. That said, it is important that your lizard has top quality vitamins and if you doubt that the brand you are using is adequate, change it, but gradually.

B Vitamins in Avitaminosis

B vitamins in general are associated with healthy nerves. If there is a deficiency of B vitamins in the lizard’s diet, then paralysis will occur, particularly of the hind legs. Iguanas are for some reason particularly prone to this problem, but again, a vitamin supplement will help prevention. 

Problems in Diagnosis

From the foregoing it is clear that diagnosis of metabolic bone disease can be difficult. Avitaminosis in general may give all of the symptoms outlined, but lack of a specific vitamin may result in only some of the symptoms. This is why it is so important to take your lizard to the vet if the early signs of skin problems and eye problems are first noticed. The vet can do a blood test for vitamin deficiency, and will probably take a detailed history. This is because the lack of some vitamins can cause very slow onset of the symptoms, due to the fact that the body can store some vitamins for some time and so the deficiency is not immediately apparent.

Therefore, a change in vitamin supplement will not necessarily result in the appearance of the symptoms for some weeks or even months. Because of this, it is sometimes difficult to match the change in supplement to what is happening to your lizard today.


As always, prevention is better than cure. However, if you have inadvertently been feeding your lizard an inadequate diet, the damage can be minimised or reversed by prompt veterinarian intervention and the addition of the missing vitamins to the diet. The lizard, if only one is affected, may need isolation until any mouth problems have been sorted out and it is back to eating properly and if the skin is sore then care must be taken that no infection gets in to the broken places.


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