Increasing evidence supports the diagnostic accuracy of epiluminescence microscopy (ELM) in the noninvasive diagnosis of mucosal pigmented lesions.1 In everyday clinical practice, routine ELM examination of mucosal lesions necessarily requires sterile instruments to prevent the potential transmission of infections between patients. Since sterilization of instrumental probes is usually difficult to perform, an adequate level of safety in routine dermoscopy procedures could be achieved by covering the instrument with disposable material.2 Suitable material should be inexpensive, easily available, prevent contamination, and permit an unmodified view of the pigmented lesions.
The results of a previous study show that polyvinyl chloride (PVC) food wrap (mean ± SD thickness, 9 ± 1 μm) (Domopak; Comital Cofresco SpA, Volpiano [Torino], Italy) covering the dermoscopy probe with the interposition of mineral oil both between the glass plate and the film and between the film and the skin does not significantly change the perception of skin colors and color differences compared with the usual ELM procedure.3 Furthermore, the submicron observation of PVC film samples performed by scanning electron microscope revealed the absence of pores on the film surface even at an original magnification of ×50 000. However, the absence of pores on the PVC surface does not exclude a potential permeability to viruses.
In the present article, we addressed this problem using the polymerase chain reaction (PCR) assay to evaluate the safety of PVC film in preventing virologic contamination of the probe and thus potential cross-contamination between patients. Herpes simplex virus 2 (HSV-2) and human immunodeficiency virus 1 (HIV-1) were chosen as challenge viruses being potential sources of probe contamination during dermoscopic scanning of mucosal surfaces.
Samples of PVC were tested as unaltered naïve samples and as samples exposed to simulated controlled clinical use in which the PVC film was placed on a dermoscopic probe with mineral oil placed on both surfaces and rubbed for 2 minutes on the skin while exerting light pressure. To verify whether the PVC film was effective in preventing diffusion of virus particles during an incubation time comparable to that needed for the dermoscopic examination, increasing concentrations of HSV-2 and HIV-1 suspended in sterile solution were placed on 1 side of the membrane and incubated in sterile conditions for up to 30 minutes at room temperature. Virus diffusion through the membrane was evaluated by PCR and reverse transcriptase–PCR. The PCR reactions had a sensitivity of about 50 copies of HIV-1 and HSV-2 in first-round amplifications, and up to 1 copy of HIV-1 and HSV-2 in nested reactions.
The results shown in the Figure and summarized in the Table demonstrate that PVC film efficiently prevented the diffusion of HSV-2 and HIV-1 for respective virus concentrations up to 107 and 106 copies/mL (corresponding to about 105 plaque-forming units for HSV-2 and 105 median tissue culture infectious dose for HIV-1). No differences were observed between control and treated membranes.
Permeability of polyvinyl chloride (PVC) film to herpes simplex virus 2 (HSV-2) and human immunodeficiency virus 1 (HIV-1). The transfer of virus particles across PVC sheets was investigated by incubating for 30 minutes 50 μL of virus suspension on 1 side of the membrane and placing it on 1 drop of phosphate-buffered saline solution. The drop was then collected and analyzed for the presence of HSV-2 and HIV-1 by polymerase chain reaction (PCR) and reverse transcriptase–PCR, respectively. Human β-actin gene was used as a control. Lane numbers indicate virus concentration, expressed as copies per milliliter. C+ Indicates positive control; gag, group-specific antigen; and UL-48, unique long 48.
Literature data show that in asymptomatic infected patients, virus shedding can be observed for both HSV and HIV in the genital mucosa, and disease must be considered potentially transmissible during clinical examinations. Human immunodeficiency virus is found in concentrations of up to 105 copies/mL in cervical swabs.4 Likewise, HSV-2 shedding can reach 105 copies/mL during asymptomatic infections.5
Our results show that PVC film completely blocks the passage of viruses even when virus concentrations are 100-fold higher than those reported in asymptomatic patients. These results were obtained in harsher conditions than would normally apply during clinical examination (ie, incubation time of 30 minutes and high viral concentrations).
Therefore, the use of PVC film during dermoscopic examination of mucosal surfaces acts as a safe barrier for virologic contamination and prevents infection in sequential patients. This could improve the role of dermoscopy in clinical assessment of mucosal melanoma from other melanocytic and nonmelanocytic mucosal pigmented lesions.
Correspondence: Dr Virgili, Department of Clinical and Experimental Medicine, Section of Dermatology, University of Ferrara, Via Savonarola 9, 44100 Ferrara, Italy (email@example.com).
Financial Disclosure: None reported.
Thank you for submitting a comment on this article. It will be reviewed by JAMA Dermatology editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest*
Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Purchase Online Access to this article for 24 hours
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 1
Customize your page view by dragging & repositioning the boxes below.
and access these and other features:
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.