title: Demodex folliculorum: its association with oily skin surface rather than rosacea lesions.
abstract: BACKGROUND
  Despite the predilection of Demodex folliculorum (DF) for human sebum, observational studies addressing a relationship between this agent and rosacea paid no attention to the effect of a potentially acting confounder, the oily nature of the skin.
  
  
  OBJECTIVE
  To analyze whether a relationship exists between the presence of the mite in rosacea and oily cutis.
  
  
  METHODS
  An observational study on 63 rosacea cases and 61 healthy controls, both discriminated according to their predominance of oily or dry cutis, was carried out to investigate demodectic density by the skin surface biopsy.
  
  
  RESULTS
  While comparisons on the density of DF revealed no differences between patients and controls (Mann-Whitney U-test, P = 0.35), persons with an oily cutis had increased amounts of this mite on the skin surface (Mann-Whitney U-test, P < 0.05), irrespective of whether they had rosacea or not.
  
  
  CONCLUSIONS
  The association between DF and oily skin rather than rosacea lesions gives no support for this agent being implied in disease pathogenesis.
authors.affiliation: Department of Dermatology, School of Medical Sciences, National University of Rosario, Rosario, Argentina.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Porta Guardia
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008925:Mites; D012393:Rosacea / Q000469:parasitology*; D012629:Sebum / Q000378:metabolism; D012737:Sex Factors; D012867:Skin / Q000378:metabolism / Q000469:parasitology*; D012879:Skin Physiological Phenomena; D013499:Surface Properties