All rats apart from laboratory rats carry Mycoplasma Pulmonis (Myco), although many spend their entire life without any showing any serious symptoms. Factors that can cause the disease to flare up include stress, a weak immune system and other illnesses.

Symptoms:

Sneezing, sniffling, lethargy, occasional squinting, labored breathing, rough hair coat, and porphyrin staining (looks like blood) around the eyes and nose. The rat may also tilt or roll its head. If the disease is untreated after the onset of symptoms, it will enter the lungs and eventually be fatal.

If your rat displays some or all of these symptoms, you should take it to a vet as soon as possible. Although Myco cannot be cured, the infection can be suppressed with antibiotics such as Baytril. Rats can have other respiratory diseases but Myco is by far the most common.

Symptoms:

Scabs

If your rat has scabs, mites or lice are the prime suspects. The shoulders, chin and neck are most likely to be worst hit. It is also possible, although less common that the scabs have been caused by fighting (assuming the rat shares a cage). You should start treating any scratch marks and scabs as caused by mites unless you have reason to think they have been inflicted during fighting. Mites or lice are best treated with Ivermectin, from your vet. You will want to make sure the vet knows what he/she is doing as an overdose will be fatal to the rat.

Protein allergy can be another cause of scabs. This may cause scabs under the chin and around the face. Reducing protein in the affected rat's diet will help if this is the cause.

Lumps are more common in does than bucks. Thankfully they are not always malignant tumours. Many are caused by benign mammary lumps or an abscess. Let your vet make the diagnoses and then treat as appropriate

Benign growths

These do not always need to be removed. If the affected rat is elderly the risk from the anaesthetic and the trauma of undergoing surgery are probably worse for the rat than doing nothing. Another factor in your decision to leave or remove a benign lump will be the extent to which it is affecting the rat's mobility. There is a good chance that a benign lump will not grow back once removed.

Abscesses

Caused by an infection, these will grow quickly and then eventually burst. When the abscess does, expect a foul smelling pus to emerge. Clean the area with salty water and ensure that all the material is out of the wound before it heals over. Otherwise the process will simply repeat itself. If the abscess does not burst it may need lancing by a vet. The rat should be on antibiotics until the abscess has completely healed.

Tumors.

Sadly some lumps are caused by malignant tumors. These spread quickly and usually reoccur even if removed. If you are having a lump removed from your rat, having it tested for malignancy will let you make an informed choice about the rat's best long term interest.

Symptoms:

Lack of balance or head tiliting.

By the time you see these visible symptoms the infection will probably be quite advanced. A steroid injection and course of antibiotics will clear up an ear infection and the symptoms. However balance and head tilting can have other causes, so if this treatment doesn't work he/she may another problem.

Symptoms:

Lack of balance and headtilting.

I.E. a stroke can appear identical to an ear infection. One or more steroid injections may help a bit, but if your rat has had a stroke you should carefully consider how much function the rat appears to have lost and what his/her remaining quality of life is when deciding on the right course of action.

Symptoms:

Initially small red bumps that resemble calluses. The bumps may become large and intermittently bleed and scab over. This can lead to chronic inflammation and abscesses.

Typically, bumblefoot starts as a wound that becomes infected. There is some debate over the role of wire mesh cage floors in causing bumblefoot. Many experienced rat owners feel such floors cause or exacerbate bumblefoot, so unless more conclusive evidence emerges, you should probably avoid cages with this kind of floor. An alternative and newer theory is that exposure to urine (eg if pooled on a solid floor) may also be implicated. The first stage of treatment for bumblefoot is a combination of antibiotics combined with cleaning and treatment of the wounds. If the lesions do not respond, surgery may be needed. However this does not always work. The best defence is to inspect your rats' feet regularly for early signs and keep their cage clean.