Finacea (azelaic acid) has been shown effective in rosacea. Antibiotics, both oral and topical, seem to work as anti-inflammatory agents in this condition, rather than as germ-killers. Elidel may be intended to reduce inflammation without the need for steroids, which can aggravate rosacea. I am not familiar with Keflex as a rosacea drug; tetracycline derivatives are the standard ones, and I don't know exactly why your doctor chose Keflex.
Best.
Dr. Rockoff