Around 1 in 10 people in the UK are thought to develop rosacea. This is a lot of people, but many cases are mild. Symptoms may first appear in your early 20s, but the usual age that symptoms appear is in your 30s-50s. Rarely, rosacea can affect children. Women are more commonly affected than men. However, rosacea is often less severe in women than in men. Rosacea is more common in fair-skinned than dark-skinned people.