If a person is being poisoned slowly or poisoning themselves with say arsenic slowly, would we call that a disease or say that the internal organs that the poison is affecting are diseased?

Or might we say that, since the skin is now recognized as an organ, that a skin burn is a disease?

If the answer to either or both of those question is no, why then do we say that drugs or alcohol or smoking is the cause of organ disease or the behavior is itself a disease?