Although the cause of rosacea is unclear and is still under scientific investigation, there has been an explosion of new products -- many available without a prescription -- that imply they may help rosacea. How can rosacea patients know whether such claims have merit?

"In the case of prescription drugs, it is required by law that they undergo clinical studies to demonstrate safety and effectiveness, and the results must be reviewed and approved by the Food and Drug Administration (FDA)," said Dr. Jonathan Wilkin, former director of the FDA's Division of Dental and Dermatologic Products. Advertising for these products -- unlike others -- can be readily identified because it must include extensive clinical information, usually shown in small type, about what the drug is used for, potential side effects and other information.

"While the FDA also monitors nonprescription drugs, I know of none that has been approved as a new drug to specifically treat rosacea," Dr. Wilkin said.

On the other hand, he noted that certain skin-care products may be used for cleansing or to potentially calm inflammation, and that green or yellow makeup can reduce the appearance of redness. "When it comes to products for skin care and cosmetic use, a patient's best bet may be to ask their physician for a recommendation best suited to their individual condition," Dr. Wilkin said.