Tandemly repetitive subelement (TRS) 1 polymerase chain reaction types of the 16 isolates of Trichophyton rubrum from 7 patients. The TRS-1 pattern of T rubrum isolated from patients 1, 2, 3, 5, and 7 was the same in both the hands and the toe webs. bp indicates base pair; F, finger; HD, dorsal surface of the hand; M, molecular mass marker; N, toenail; P, palm; S, sole; and TW, toe web.
Byung Cheol Park, Seok-Jong Lee, Do Won Kim, Byung Soo Kim, Ho Youn Kim, Jong Soo Choi, Eun-So Lee, Weon Ju Lee. Molecular Identification of Mycologic Correlation in Patients With Concomitant Tinea Pedis and Tinea Manuum Infection. Arch Dermatol. 2009;145(2):205–207. doi:10.1001/archderm.145.2.205
Tinea manuum is usually combined with tinea pedis or toenail onychomycosis. In 2 feet–1 hand syndrome, tinea manuum has a tendency to develop on the hand used to excoriate the infected feet.1 Therefore, it has been postulated that the infected feet may be the sites from which the fungal infections spread to other body areas.2 However, there have been few reports clarifying the mycologic correlation in the coexistence of tinea manuum and tinea pedis, although many epidemiologic studies have been performed.
In the present preliminary study, we investigate the mycologic links between tinea manuum and tinea pedis in the same patient by analyzing the molecular characteristics of Trichophyton rubrum.
A total of 16 specimens were evaluated (7 from the hands, 6 from toe webs, 2 from toenails, and 1 from the sole) from 7 patients with concomitant tinea manuum and tinea pedis. All specimens were cultured on Sabouraud agar at 24°C for 1 to 2 weeks, and 1 colony from each culture plate was individually subcultured on Sabouraud agar for another 2 weeks.
To identify the T rubrum strain, we extracted T rubrum genomic DNA from the fungal plate culture. Using polymerase chain reaction (PCR), we then amplified the copy number of 2 tandemly repetitive subelements (TRS-1 and TRS-2) in the ribosomal DNA nontranscribed spacer (NTS) regions, as previously described.3,4
Only T rubrum grew from all 16 fungal cultures on Sabouraud dextrose agar slant plates, and all strains showed port-wine stain. On the strain typing of T rubrum by specific PCR amplification of the TRS-1 repeat regions, a total of 6 types of TRS-1 were observed among the 16 isolates (Table). In 5 of our 7 patients, the strain of T rubrum causing concomitant tinea pedis and tinea manuum in the same patient was identical (Figure). In the NTS region containing TRS-2, all 16 strains from all 7 patients were identical—TRS-2, PCR type II.
Tinea manuum is often secondarily caused by the fungus spreading from foot to hand, and the same fungus infects the feet, hands, and nails concomitantly in most cases.5 In the present study, only T rubrum grew on fungal cultures from all specimens. The same dermatophyte, T rubrum, infected the hands, toenails, and toe webs simultaneously, but we did not know whether the same strain of T rubrum caused tinea manuum and tinea pedis simultaneously in the same patient. Our results showed that the same strain of T rubrum induced both tinea manuum and tinea pedis in 5 of 7 patients with concomitant tinea manuum and tinea pedis. We therefore postulate that most causative fungi of tinea manuum might originate from the infected foot in the same patient.
However, not all of our patients with concomitant tinea manuum and tinea pedis showed the same strain of T rubrum. Therefore it is likely that multiple strains of T rubrum caused the tinea pedis and tinea manuum infections, or the dermatophyte of the hands was transmitted from a source other than the infected foot.
Correspondence: Dr W. J. Lee, Department of Dermatology, Kyungpook National University Hospital, 50 Samdeok 2-ga, Chung-Gu, Daegu, South Korea, 700-721 (firstname.lastname@example.org).
Author Contributions: Dr W. J. Lee had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Park, S.-J. Lee, D. W. Kim, B. S. Kim, H. Y. Kim, Choi, and W. J. Lee. Acquisition of data: Park, S.-J. Lee, D. W. Kim, B. S. Kim, H. Y. Kim, Choi, and W. J. Lee. Analysis and interpretation of data: Park, S.-J. Lee, D. W. Kim, B. S. Kim, H. Y. Kim, Choi, E.-S. Lee, and W. J. Lee. Drafting of the manuscript: Park, S.-J. Lee, D. W. Kim, B. S. Kim, H. Y. Kim, Choi, and W. J. Lee. Critical revision of the manuscript for important intellectual content: Park, S.-J. Lee, D. W. Kim, B. S. Kim, H. Y. Kim, Choi, E.-S. Lee, and W. J. Lee. Administrative, technical, and material support: Park, S.-J. Lee, D. W. Kim, B. S. Kim, H. Y. Kim, Choi, and W. J. Lee. Study supervision: Park, S.-J. Lee, D. W. Kim, B. S. Kim, H. Y. Kim, Choi, and W. J. Lee.
Financial Disclosure: None reported.