The cause of rosacea is unknown, but it could be due to a combination of hereditary and environmental factors. Rosacea is not caused by poor hygiene. A number of factors can trigger flare-ups, including: Hot drinks and spicy foods.
Use mild products such as rice powder cleanser and white boxed complexion bar. Add hydration with pure skin quench and gold elixir is also good to calm the rosacea down. 
Treating rosacea at home
  1. Use a daily gentle cleanser.
  2. Avoid perfumed soap and alcohol-based products.
  3. Blot your face dry or let it dry naturally.
  4. Use a sun block with an SPF (sun protection factor) of at least 30 and wear a hat on sunny days.