I found this today and it makes me wonder? Bunny Button did have an abscess!

Pasteurellosis: A highly contagious illness among rabbits caused by a bacterial infection that can rapidly lead to a rabbit's death. The symptoms can include white or yellow discharge from the nose, runny eyes, frequent sneezing, coughing, and difficulty breathing. Often a rabbit with Pasteurellosis will have matted, crusty fur on the front paws from attempting to wipe away the discharge from the nose. Pasteurellosis usually starts as an infection in the sinuses and can spread to the eyes or organs elsewhere in the body, encourage pneumonia, cause abscesses particularly in head and jaw, and infect the inner ear, causing the head to tilt. Pasteurellosis is caused by the Pasteurella Multocid organism, which is thought to reside naturally in most rabbits' sinuses but can multiply under certain conditions--such as in stressful situations or in older rabbits or very young ones--and cause illness and death. Pasteurellosis can be difficult to treat. Sometimes what appears as Pasteurellosis is actually a cold or another bacterial infection, which is generally treatable. Also called Pasteurella or snuffles.