Table 2.
Comparison of Demodex Prevalence and High Demodex Density Between Normal Healthy Skin, Acne Vulgaris Only, and Acne with Nonspecific Facial Dermatitis Group, Based on SSSB and SNS
| SSSB / SNS | Normal Healthy Skin (n=40) | Acne Vulgaris Only (n=40) | Acne with Nonspecific Facial Dermatitis (n=40) | P value* | P value** | P value*** |
|---|---|---|---|---|---|---|
| Demodex prevalence, n (%) | ||||||
| ○ SSSB ≥1 mite/cm2 | 7(17.5) | 9(22.5) | 24(60.0) | 0.576 | <0.001 | 0.001 |
| ○ SNS ≥1 mite/5 pustules | – | 3(7.5) | 8(20.0) | – | – | 0.096 |
| ○ SSSB and SNS | 7(17.5) | 9(22.5) | 25(62.5) | 0.576 | <0.001 | <0.001 |
| High Demodex density, n (%) | ||||||
| ○ SSSB ≥6 mite/cm2 | 3(7.5) | 5(12.5) | 15(37.5) | 0.356 | 0.001 | 0.010 |
| ○ SNS ≥3 mite/5 pustules | – | 2(5.0) | 6(15.0) | – | – | 0.132 |
| ○ SSSB and SNS | 3(7.5) | 5(12.5) | 16(40.0) | 0.356 | 0.001 | 0.005 |
Notes: P value* - Comparison between normal healthy skin group with acne vulgaris only group. P value** - Comparison between normal healthy skin group with acne and nonspecific facial dermatitis group. P value*** - Comparison between acne vulgaris only group with acne and nonspecific facial dermatitis group. Chi-square or Fisher’s exact tests were used for hypothesis testing.
Abbreviations: SSSB, Standardized Skin Surface biopsy; SNS, Superficial Needle Scraping.