Vaccination reactions are fairly common in horses, and usually result in local swelling, soreness, reduced appetite and depressed attitude.
Less common but more severe allergic reactions to vaccines may result in hives full-blown body-wide anaphylaxis, which develop suddenly and can be life threatening. Blood pressure can drop dramatically. Horses can have trouble breathing or have diarrhea or colic. Usually, rapid treatment is needed in order to save the horse.
New vaccines are tested to reduce adverse reactions but there is always a possibility of reaction. If a horse has reacted once to a vaccine, the reaction could be more serious the next time. Your vet will keep a record of this reaction to prevent similar problems in the future. They may discuss vaccine alternatives with you. If the reaction is severe, they may discuss the problem with the vaccine manufacturer.
Other Diagnoses Considered
Treatments May Include
Prognosis & Relevant Factors
The prognosis for simple local inflammatory types of reactions is good. The prognosis for full-blow anaphylactic allergic reaction is always guarded, as they often require immediate and appropriate treatment.
I Might ObserveRelated Observations
QUESTIONS TO ASK MY VET