Ask the vet - Dog
Is conjuntivitis in dogs contagious?
Vet at FirstVet answers:
It is very rare that conjunctivitis is contagious between dogs (or to you for that matter!).
Contagious conjunctivitis is usually caused by herpes virus. When a dog gets conjunctivitis it is more often caused by something in the environment that has irritated the eye. Dogs that reside in the same environment can therefore get conjunctivitis at the same time even though the conjunctivitis itself is not contagious.
If a dog repeatedly gets conjunctivitis it is likely due to an underlying cause (i.e. dry eye/KCS, eyelid deformity, allergy, obstruction in the tear canal, etc).