Background: Recently, adult acne has increased with the infestation of fungal and Demodex due to use of poor quality cosmetic products.
Objective: To define the prevalence of fungal and Demodex infestation and its related factors on adult acne at Can Tho Dermatology Hospital, Vietnam.
Materials and Methods: A cross-sectional descriptive study on 134 adult acne patients at Can Tho Dermatology Hospital, Vietnam.
Results: The study from 8/2014 to 3/2015 recorded the prevalence of fungal and Demodex infestation on adult acne patients which were 29.1% (Demodex 26.1% and fungi 3%). Related factors were tingling sensation (p = 0.017, OR = 2.5), no papules or pustules (p = 0.016, OR = 0.362), lesions on the cheeks (p = 0.047, OR = 0.68), clinical characteristics (p = 0.002), dry skin and scaling (p<0.001, OR = 22).
Conclusion: The prevalence of fungal and Demodex infestation on adult acne patients was 29.1%. Adult acne patients with tingling feeling, dry skin and scaling, acne comedones and most of lesions on the cheeks had higher possibility of fungal and Demodex infestation.

Keywords: Demodex, Fungal, Adult acne