Deformities of the area between the canthi rostrales and their meaning for chameleon health

Picture legends: 

Upper row left to right: 1. Healthy wild male Chamaeleo zeylanicus with physiologically formed area between canthi  rostrales, 2. starting proliferation of infection pressure in combination with mouth-rot in a captive female of Chamaeleo calyptratus, 3. skull of female Furcifer pardalis with clearly visible prefrontal fontanellas

Lower row: Acute sinus infection with heavily bulged area between canthi rostrales right above the prefrontal fontanellas combined with conjuctivitis and RI in a captive female of Chamaeleo calyptratus

From time to time, chameleon keepers notice some strange bulges - deformities on the top of the nasal area of the head, between the level of the nostrils and the level of the eyes. They can appear bilaterally (more often) or only on one side. They are sign of a serious state which needs an immediate action, as it is life threatening!

Let us first understand what it is and how it is caused.

The anatomy of chameleon head is quite complex. The form of the head is usually pyramidal, with very clearly expressed crests (ridges), which are specifically named according to their position on the head and the underlaying bones.

In all chameleon species, you can find a very prominent crest, extending from the top of the snout just above the mouth tip and running towards the eye. These structures are called the rostral crests (lat. in plural canthi rostrales; singular canthus rostralis) and form the first (rostral) part of the three parts of the s.c. lateral crests (lat. canthi laterales) - they extend in many species either to the top of the casque or to the temporal edge of the casque as the ocular or supraocular crest (canthus ocularis/supraocularis) and finally the proper lateral crest (canthus lateralis proprius). Some authors wrongly call them the canthal crests but it is a incorrect, as "canthal" is related to a crest a "crest" is a crest, so a "crest related to crest" is obviously a nonsense, same like e.g. an acoustic sound or dermal skin :-)

Right between these rostral crests the bulges can appear. The question is: how a bone forming the upper surface of the snout/forehead can be bulged? To find out the answer to this question, we need to look in more detail on the bone structure of this area of the snout area of the head is formed by a plate frontal bone (os frontale) and parts of the prefrontal bones (ossa praefrontalia). But, there are two fontanellas - openings just between the prefrontal bones. They lay above the s.c. nasal cavities (lat. choannae) situated above the hard palate (lat. palatum durum). So, the bulges being observed are not bone-based but are in fact formed either by swellings of the underlaying soft tissues from the choannae or by liquid - effusion or pus which was created thanks to some inflammation process inside the nasal cavities and through blocked openings it was pressurized and proliferates over the level of the head surface pushing the skin out forming those bulges. To make the story short, the bulges are pressurized pus formed in nasal cavities by an inflammation.

As the nasal cavities are part of the respiratory tract, very often, a Respiratory Infection (RI) is present too.

As the nasal cavities communicate through the crossing of larynx and pharynx with the mouth cavity, mouth rot or inflammation of the tongue, gingives, jaws, temporal glands can be present too.

As the nasal cavities are connected to the eye conjunctive sac via nasolacrimal duct (lat. ductus nasolacrimalis), the pressurized liquid/pus can easily penetrate eyes and cause inflammation and damage there too.

Obviously, once you see those bulges between canthi rostrales, you have no time to wait. The situation is severe and life threatening, and every minute can be critical. Thanks to the complexity of the problem, it is a call for a competent VET, who will very likely do the following:

• inspection of the animal,
• puncture of the pressurized area to extract the pus and clean and disinfect it locally,
• prescribe both local and holistic antibiotics (best after a smear is cultivated and after a sensitivity test is conducted),
• treat also other affected organs or systems.

The prognosis is relatively bad. Most of animals die short after showing these symptoms, because it is simply too late. If healed, they do not live long as a rule.

What is the reason for such a serious disorder?

Only and solely wrong care:

wrongly ventilated cage,

overheating,

misting at daytime,

wrong supplementation,

no bee pollen,

no prevention.