Demodex spp. as a possible aetiopathogenic factor of acne and relation with acne severity and type

Introduction
Acne is a very common skin disease in adolescents and young adults, but it also affects adults. However, its aetiology is not yet fully understood. Demodex appears to be associated with multiple skin disorders, but controversy persists. Some reports indicate a connection between acne vulgaris and demodicosis.

Aim
To confirm the association between Demodex infestation and acne vulgaris.

Material and methods
A total of 108 patients were enrolled in the acne group. Acne severity was calculated as GASS and acne type (adolescent and post adolescent) was recorded. An age-sex matched healthy control group comprising 65 individuals were included in the study. Dermatological examinations were performed and an SSSB was used to determine the presence of Demodex.

Results
In our study, Demodex positivity was seen in 46 (42.6%) patients in the acne group and 8 (12.3%) in the control group; this difference was statistically significant (p < 0.001). A multivariate Backward Step-By-Step Logistic Regression analysis identified the most effective factors for acne development such as Demodex positivity (OR = 5.565, 95% CI: 2.384–12.99 and p < 0.001) and age under 25 years (OR = 2.3 and 95% CI: 1.183–4.473 and p = 0.014). Alcohol consumption was related to Demodex positivity (p = 0.019) in post adolescent acne.

Conclusions
Our study is the first one to evaluate acne severity, acne type and the relationship to Demodex prevalence. We suggest that Demodex infestation should be considered when the classical therapies are ineffective especially in cases of post adolescent acne.