Latent diseases tend to come to life during times of stress. Dr. Reisner says some cats carry a latent upper respiratory virus. When the cat is boarded and comes home sneezing with an upper respiratory infection, people assume that the cat picked up the infection at the kennel. This isn't always true. The stress of being boarded may have triggered the latent virus.
Stress causes other health problems, too.
Psychogenic alopecia and psychogenic dermatitis are fur loss conditions caused by the cat excessively licking or grooming itself. Such behavior ordinarily has a physical cause, like fleas but is occasionally linked to stress. Whatever the cause, organic or psychological, once adopted, the licking behavior may continue as a bad habit, and eventually lead to self-mutilation. The Diagnostic Dilemma Stress is difficult to diagnose because the symptoms are so varied, and can indicate any number of organic diseases. You should keep of record of the events that cause you concern, including when and where they occurred, and give your veterinarian a detailed description of the cat's normal behavior.