A Case-Control Study in Primary Care Settings on the Roles of Dermatoscopy in Infectious Diseases Affecting the Skin, Part 1: Viral and Bacterial Infections.

We aimed to investigate roles of dermatoscopy in skin infections, with Part 1 of our report covering viral and bacterial infections. A case-control study was conducted on the medical records of all patients with skin infections who had had dermatoscopy performed over a period of 3 months. Our control participants were all patients with skin infections in two 3-month periods, and sex-pair-matched patients with the same infections, who had not undergone dermatoscopy. Records of 523 study subjects were analyzed. Our first new finding was that dermatoscopy brought forward the diagnosis of herpes zoster by 1.62 days (95% confidence interval [CI] 0.29 to 0.34 days; z-score -2.18). Second, dermatoscopy facilitated the diagnosis of genital (P<.01) and small extragenital risk ratio [RR] 1.28, 95% CI 1.03 to 1.59) viral warts. Third, patients with genital herpes and/or genital warts and/or genital molluscum contagiosum diagnosed by clinical examination and dermatoscopy were significantly more willing to pay US$300 to investigate for other sexually transmitted infections (STIs) (RR 2.52, 95% CI 1.32 to 3.18), and bring partners for investigation (RR 1.32, 95% CI 1.12 to 1.55), compared to patients diagnosed by clinical examination alone. We performed dermatoscope-guided laser ablation on viral warts, and dermatoscopy-guided excisional biopsy to confirm molluscum contagiosum. We conclude that dermatoscopy contributes to the diagnosis of some viral and bacterial infections. In addition, it may modify the help-seeking behaviour of patients with STIs.