When a rat is sneezing excessively or making the odd pigeon noises for at least 3 days, you can try a few things:

 

• Check for environmental irritants. Are you using suitable litter/substrate/bedding? Have you removed all scented items from the room? Have you closed the windows when there is a high pollen count? Are they due a clean-out/deep clean? Have they just had a clean-out? Has the heating been on today and caused a drastic change in temperature? Has someone been smoking near the rats? Is there mould somewhere?
   

• Is there general unrest in the group or another source of stress? If so, reevaluate the group dynamic (reintros or split the group), and address the source of stress.
   

• Try a short course of metacam (consult with your vet) to ease any irritation.
   

• Try a dose of ivermectin. Sometimes reducing the rat's parasite load takes some additional pressure off their immune system and allows them to work through the issue better. If they are young, parasitic bronchitis could be an option - this is where bladder threadworms are present, and the larvae can migrate to the lungs. The presence of bladderworms is difficult to diagnose due to their irregular expulsion via urine and preference for burrowing deeply into the bladder's mucosal surface.
   

• In the case of sneezing/general snottiness, consider the possibility of allergies. If this is likely, try a course of piriton (consult with your vet). I have personally never used piriton with my rats, but I know others who have.

 

If this develops into consistent pigeon noises despite removing potential irritants over the course of another few days and/or their chest sounds crackly (can hold their chest to your ear to see if the sound is nasal or chesty), consult your vet. If their lungs sound crackly then they have a Upper Respiratory Infection (URI) and they should put the rat on a course of doxycycline + baytril + metacam for 2-3 weeks, longer if the symptoms don’t resolve within that time. Baytril and metacam rarely resolves these issues, though I have had mild URIs resolve with doxy and metacam.

 

A rat may develop lung scarring after a bad URI or repeated URIs. In this circumstance, management should be your main priority. Management will involve monitoring and mitigating for environmental irritants, and with time you will get to know what your rat is sensitive to. Treatment with antibiotics should only be done when they are consistently noisy or if they start showing other symptoms of having an infection. Overuse of antibiotics can contribute to antibiotic resistance, and if there is no active infection then there is no real reason for their use.

 

Nebulising is commonly suggested by vets. However, I would only suggest using it as a form of management for rats who have chronic issues, and ONLY if they tolerate it well. Many rats find nebulising stressful which can make their symptoms worse; the benefits have to outweigh the costs in order for it to be worthwhile. I have the Omron C28P nebuliser and diluted F10 antiseptic. I place the rat in the carrier with the lid resting closed rather than completely closed. This allows the mouthpiece to feed through, and it also allows the rat to come out if they find it stressful. I put the machine a bit further away and turn it on so that it’s not as loud. I then feed the mouthpiece into the carrier, and drape a blanket that I’m not precious about over the carrier, which also holds the mouthpiece in position. I tend to leave them from 5-15 minutes depending on the rat, and repeat twice daily as needed. If you notice an improvement in symptoms and the rat finds it tolerable, then it's worth doing.

 

If the rat is mouth-breathing, as shown in the video below kindly provided by Su Oakley, they require immediate veterinary attention as the rat is in respiratory distress. Respiratory distress shouldn't be confused with choking, where the rat pulls their head and ears back. If the rat is showing signs of pneumonia (lethargy, laboured breathing, hunched posture, puffed fur etc), then they require immediate veterinary attention.