Clinical and Onychoscopy Patterns in Fingernail Onychomycosis—A Study by the International Dermoscopy Society Trichoscopy And Onychoscopy Task Force
Abstract
Introduction: Onychomycosis is one of the most common nail diseases. Fingernail onychomycosis is significantly less frequent than toenail onychomycosis and it is often misdiagnosed due to its subtle clinical presentations.
Objectives: We sought to analyze the clinical and onychoscopic features of culture-proven cases of fingernail onychomycosis in adult and pediatric patients.
Methods: Medical records of 120 patients with onychomycosis limited to the fingernails were collected and analyzed across several dermatological centers (Italy, Switzerland, Spain, Greece, Brazil, India, Morocco, Tunisia). Data collected included age, sex, affected hand, affected fingernails, isolated fungal microorganism, clinical, and onychoscopic signs.
Results: A total of 341 fingernails were analyzed. The most commonly affected hand was the right one ,and the most frequently affected digits were the second and third. The mean number of affected digits per patient was 2.84. Cultures identified Trichophyton rubrum in 54 cases, T. mentagrophytes var. interdigitalis in 20 cases, Aspergillus spp. in 8 cases, Candida spp. in 31 cases, and various other fungi in the remaining cases. Major clinical and onychoscopic features observed included onycholysis, subungual hyperkeratosis, leukonychia, chromonychia and absence of the cuticles. On the basis of all findings, 4 main types of fingernail onychomycosis were identified.
Conclusions: Fingernail onychomycosis presents with distinct clinical and onychoscopy characteristics that can overlap with other nail conditions. Dermoscopy enhances diagnostic accuracy, but mycological confirmation is mandatory for a definitive diagnosis.
References
Gupta AK, Stec N, Summerbell RC, et al. Onychomycosis: a review. J Eur Acad Dermatol Venereol. 2020;34(9):1972-1990. DOI: 10.1111/jdv.16394. PMID: 32239567.
Gupta AK, Wang T, Polla Ravi S, Mann A, Bamimore MA. Global prevalence of onychomycosis in general and special populations: An updated perspective. Mycoses. 2024;67(4):e13725. DOI: 10.1111/myc.13725. PMID: 38606891.
Gupta AK, Wang T, Cooper EA, et al. A comprehensive review of nondermatophyte mould onychomycosis: Epidemiology, diagnosis and management. J Eur Acad Dermatol Venereol. 2024;38(3):480–495. DOI: 10.1111/jdv.19644. PMID: 38010049.
Borba OSM, Ogawa MM, Kirsztajn GM, Tomimori J. Onychomycosis in immunocompromised population: Phenotypic and molecular identification. Mycoses. 2023;66(11):1018-1024. DOI: 10.1111/myc.13634. PMID: 37488648.
Tosti A, Piraccini BM, Ghetti E, Colombo MD. Topical steroids versus systemic antifungals in the treatment of chronic paronychia: an open, randomized double-blind and double dummy study. J Am Acad Dermatol. 2002;47(1):73-6. DOI:10.1067/mjd.2002.122191. PMID: 12077585.
Gupta AK, Taborda VBA, Taborda PRO, Shemer A, Summerbell RC, Nakrieko KA. High prevalence of mixed infections in global onychomycosis. PLoS One. 2020;15(9):e0239648. DOI: 10.1371/journal.pone.0239648. PMID: 32991597.
Haneke E. Fungal infections of the nail. Semin Dermatol. 1991;10(1):41-53. PMID: 2018719.
Kyriakou A, Zagalioti SC, Trakatelli MG, et al. Fungal Infections and Nail Psoriasis: An Update. J Fungi (Basel) 2022;8:154. DOI: 10.3390/jof8020154. PMID: 35205908.
Rigopoulos D, Papanagiotou V, Daniel R 3rd, Piraccini BM. Onychomycosis in patients with nail psoriasis: a point to point discussion. Mycoses 2017;60:6-10. DOI: 10.1111/myc.12542. PMID: 27523738.
Zaias N, Escovar SX, Rebell G. Opportunistic toenail onychomycosis. The fungal colonization of an available nail unit space by non-dermatophytes is produced by the trauma of the closed shoe by an asymmetric gait or other trauma. A plausible theory. J Eur Acad Dermatol Venereol. 2014;28(8):1002-6. DOI: 10.1111/jdv.12458. PMID: 24708482.
Haneke E, Stovbyr G. Post-Traumatic Single-Digit Onychomycosis. J Fungi (Basel). 2023;9(3):313. DOI: 10.3390/jof9030313. PMID: 36983481.
Elewski BE. Onychomycosis: pathogenesis, diagnosis, and management. Clin Microbiol Rev. 1998;11(3):415-29. DOI: 10.1128/CMR.11.3.415. PMID: 9665975.
Piraccini BM, Alessandrini A. Onychomycosis: A Review. J Fungi (Basel). 2015;1(1):30-43. DOI: 10.3390/jof1010030. PMID: 29376897.
Tosti A, Baran R, Piraccini BM, Fanti PA. "Endonyx" onychomycosis: a new modality of nail invasion by dermatophytes. Acta Derm Venereol. 1999;79(1):52-3. DOI: 10.1080/000155599750011714. PMID: 10086860.
Lipner SR, Scher RK. Onychomycosis: Clinical overview and diagnosis. J Am Acad Dermatol. 2019;80:835-51. DOI: 10.1016/j.jaad.2018.03.062. PMID: 29959961.
Piraccini BM, Balestri R, Starace M, Rech G. Nail digital dermoscopy (onychoscopy) in the diagnosis of onychomycosis. J Eur Acad Dermatol Venereol. 2013;27:509-13. DOI: 10.1111/j.1468-3083.2011.04323.x. PMID: 22040510.
Kayarkatte MN, Singal A, Pandhi D, Das S, Sharma S. Nail dermoscopy (onychoscopy) findings in the diagnosis of primary onychomycosis: A cross-sectional study. Indian J Dermatol Venereol Leprol 2020;86:341-9. DOI: 10.4103/ijdvl.IJDVL_100_19. PMID: 32415047.
Litaiem N, Mnif E, Zeglaoui F. Dermoscopy of Onychomycosis: A Systematic Review. Dermatol Pract Concept. 2023;13(1):e2023072. DOI: 10.5826/dpc.1301a72. PMID: 36892372.
Ramos Pinheiro R, Dias Domingues T, Sousa V, Galhardas C, Apetato M, Lencastre A. A comparative study of onychomycosis and traumatic toenail onychodystrophy dermoscopic patterns. J Eur Acad Dermatol Venereol. 2019;33(4):786-792. DOI: 10.1111/jdv.15358. PMID: 30468535.
Haneke E. Nail psoriasis: clinical features, pathogenesis, differential diagnoses, and management. Psoriasis (Auckl). 2017;7:51-63. DOI: 10.2147/PTT.S126281. PMID: 29387608.
Sar-Pomian M, Starace M, Lencastre A, et al. Dermoscopic Nail Changes in Psoriasis, Lichen Planus, and Lichen Striatus. Skin Appendage Disord. 2024;10(4):273-292. DOI: 10.1159/000538581. PMID: 39021761.
Rachadi H, Chiheb S. Dermoscopic features of nail psoriasis: a systematic review. Int J Dermatol. 2024;63(8):1013-1019. doi: 10.1111/ijd.17138. PMID: 38520074.
Litaiem N, Nakouri I, Bouhlel S, Mansour Y, Bouchakoua M, Zegaloui F. Dermoscopic Features of Toenail Onychomycosis. J Am Podiatr Med Assoc. 2020;110(3):Article_4. DOI: 10.7547/18-102. PMID: 32730601.
Iorizzo M, Starace M, Pasch MC. Leukonychia: What Can White Nails Tell Us? Am J Clin Dermatol. 2022;23:177-93. DOI: 10.1007/s40257-022-00671-6. PMID: 35112320.
Gupta AK, Taborda P, Taborda V, et al. Epidemiology and prevalence of onychomycosis in HIV-positive individuals. Int J Dermatol. 2000;39(10):746-53. DOI: 10.1046/j.1365-4362.2000.00012.x. PMID: 11095193.
Gelotar P, Vachhani S, Patel B, Makwana N. The prevalence of fungi in fingernail onychomycosis. J Clin Diagn Res. 2013;7(2):250–2. DOI: 10.7860/JCDR/2013/5257.2739. PMID: 23543802.
Miller RC, Lipner SR. Distinct patient characteristics and pathogenesis of fingernail only vs. fingernail and toenail onychomycosis in a retrospective single-centre academic study. J Eur Acad Dermatol Venereol. 2023;37(1):e116-e118. DOI: 10.1111/jdv.18552. PMID: 35986705.
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Copyright (c) 2025 Matilde Iorizzo, Bianca Maria Piraccini, Aurora Alessandrini, Francesca Bruni, Laura Vollono, Francesca Pampaloni, Nilton Gioia Di Chiacchio, Nilton Di Chiacchio, Juan Jimenez-Cahue, Chander Grover, Zoe Apalla, Asmahne Souissi, Awatef Kelati, Eirini Kyrmanidou, Elizabeth Lazaridou, Michela Starace

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