Horse Veterinary Questions? Ask an Equine Vet.
I am sorry to hear that your horse is not feeling well. Rule outs for unilateral nasal discharge include dental disease (an abscessed tooth root most commonly), sinusitis (inflammation of the sinuses which may be infectious or allergic in origin), a nasal tumor (this may be benign or cancerous but is generally rare), a fungal or bacterial infection (rare to common depending on the area you are in). As dental conditions are the most common, you should schedule an appointment for your vet to come out and do a sedated oral exam with dental x-rays. Does this address your question today? Please let me know if you need more information.