Your observation is not the same thing as a veterinarian’s diagnosis.
For many observations, it is impossible to know what the best treatment is, because there are multiple conditions (diagnoses) that cause the same apparent sign (observation) in the horse.
Your vet may choose to provide symptomatic treatments aimed at improving a sign of disease without a diagnosis. However, care must be taken to consider the effects of those treatments in light of the ultimate diagnosis.
If a particular treatment is mismatched to the actual diagnosis, it could be a waste of time, energy and money. It can also result in harm to your horse.
Your veterinarian uses veterinary diagnostics to reach to a diagnosis. Once that is obtained, the best treatment plan can be determined, and a prognosis can be made.
For a more detailed explanation of these relationships see the two related Topics that are linked to this record under the More tab: The Value of a Diagnosis & What’s Wrong with Mr. Ed.