It has been speculated for some time that infection with parasites of the human cysticercosis species (Demodex folliculorum) increases the risk of developing rosacea. Ya Zhao from Jiaotong University in Xi'an (China) and colleagues recently analysed the results of 48 studies in 10 countries involving tens of thousands of participants.

According to a publication in the August issue of the journal Archives of Dermatology, infection with the parasite in question actually appeared to increase the risk of rosacea. This was especially true in cases where there were particularly many specimens of the human nematode in a given patient.