Why is my rat producing red tears?
Rats possess a third eyelid which has an extra lacrimal gland (tear gland) behind the eye called the Harderian gland. The Harderian gland produces secretions which help to lubricate the eye. These secretions might also play a role in pheromone related behaviours (a type of chemical messenger) as well as helping to protect the retina from UV light. The red tears can also be seen at the nostrils too and might be seen as orangey red crusting. The colour can vary in intensity but can give the appearance that the rat has been crying or sneezing blood.
Many owners are understandably incredibly worried the first time that they notice these red tears, however it is not always an indicator of a problem.
The Harderian gland produces porphyrin, this makes the tears appear red tinged. The technical name for this is chromodacryorrhea. The tears can fluoresce under ultraviolet light.
Normally these secretions from the eye are spread across the body during the process of grooming. However, in stressful situations and in the case of some illness or disease tears may overflow and it can appear as if there is bleeding coming from the eyes and nose. This is most commonly seen in rats.
What type of stressors might cause a rat to start producing red tears?
- Poor nutrition
- Illness (e.g., respiratory disease bacterial or viral, tumours, dental disease)
- Lack of water
- Pain or discomfort
- Environmental stress (e.g., lack of enrichment, lack of space or overcrowding, conflict with cage mates, handling, household noise)
- Environmental or airborne irritants (e.g., bedding, cigarette smoke, fragranced candles)
- Blocked tear duct
- Eye conditions such as injuries or infections.
What should I do if my rat has red tears?
Often the visible appearance of red tears is short lived, however seek advice from a vet if you are concerned about your rodent’s health. Because red tears can occur when a rat is in poor health it is wise to seek a veterinary check-up, this is especially prudent if your rat is showing any other signs or symptoms.
If your rat is in good health, it would be wise to check that there aren’t any sources of stress which could be the cause of the red tears. Seemingly innocuous changes to us such as the addition of an air freshener could be a source of stress to our rodent friends.
Not all “red tears” will be due to chromodacryorrhea, obviously the possibility of injuries causing bleeding should not be ignored. Fighting or bites between cage mates can sometimes lead to bleeding wounds and so it is important to check over your pet carefully.
It is worth being aware that the production of red tears usually increases over the course of a rat’s life until they are two years old. After two years of age the production of red tears reduces.
How do vets manage chromodacryorrhea?
When presented with a rat with red tears your vet will first want to perform a full clinical examination. This allows the vet to pick up any problems or abnormalities. Depending on what is found during the examination further tests might be recommended if needed such as a blood test. Management of the condition will be individual based on the underlying cause. In many cases the chromodacryorrhea will not be due to illness, and therefore reviewing the rats living conditions and potential environmental stressors will be key.