Rosacea was also known as Acne rosacea and was thus a sub-type of acne. Actually, this is the better name, because the rosacea has much in common with the acne and so the reference to acne would be recognized in the name.
Different factors are discussed in the development of rosacea and the cause is unknown as with other forms of acne. The hair follicle mites are granted a participation in the rosacea. The Center of Competence is dedicated to research into the cause and here the hair follicles mites are in the center of attention.
Hundreds of patients have been tested for Demodex mites in the past 15 years, and there have been surprising associations. Infestation and severity of the disease seem to be linked.
The immune system and the hormone situation also seem to play a role. Further research will hopefully bring new insights here.