A sufferer from a factitious disorder may deliberately injure himself, eat mouldy food in the hope of catching salmonella, or a whole range of other possibilities. Or he may simply put on symptoms of, say, a ruptured appendix.

Malingerers are not sufferers of factitious diseases; they are trying to get something specific, like time off school or a warm bed for the night.

Most factitious disorders involve feigning or causing the same disease, and going to the same hospital for treatment. These patients are usually possible to cure if the disorder is spotted. The major exception to these is Munchausen's Syndrome.

Sources:
http://www.merck.com/pubs/mmanual/section15/chapter185/185d.htm
http://psychological.com/factitious_disorders.htm