When applying azelaic acid, make sure that you do not put it anywhere in your eyes, nose, mouth, rectum, or vagina. If you’ve done so accidentally, rinse the applied area with water.
Likewise, make sure to avoid applying azelaic acid to skin that has yet to heal from sunburns, windburns, dryness, soreness, irritation, or cuts.
To avoid further skin irritation, don’t use skin products that involve harsh soaps or skin cleansers or products that have alcohol, spices, astringents, or lime.
Your doctor may also warn you against spicy foods, hot foods/drinks, alcohol, and many other foods and drinks that might make your skin flushed or red.