The most prevalent risk factor for developing onychomycosis is advanced age. Other risk factors include warm climate, peripheral vascular disease, and diabetes mellitus. Immunocompromised conditions are also thought to be linked to the prevalence of onychomycosis, especially those caused by non-dermatophyte species. It should also be noted that onychomycosis and nail trauma often coexist, with nail trauma often being a predisposing factor for the development of onychomycosis.
The majority of onychomycosis cases are caused by dermatophytes with fewer cases involving yeasts and saprophytic species. In this case, the isolated pathogen was a saphrophyte of the Fusarium genus. The most opportunistic of this species include F. solani complex, F. oxsporum complex and F. fujikorai complex. Most commonly these species cause onychomycosis in tropical countries however they are also present in temperate and artic climates with recent reports of Fusarium as a common pathogen in central European countries.
Multiple treatment options exist for onychomycosis. Medications exist in both oral and topical forms. Furthermore other options for treatment such as mechanical and chemical avulsion exist. Topical treatments are often reserved for superficial white onychomycosis or distal subungual onychomycosis affecting less than 50 percent of the nail surface. Ciclopirox 8% nail lacquer is a common topical treatment, which involves once daily application of the medication for 48 weeks. However, it is recommended that a solvent be used on the nail once weekly to remove the build up of the lacquer and therefore increase the penetration of the medication. Oral treatment options are often a better option for proximal subungual onychomycosis or onychomycosis that is involving more than 50% of the nail plate. Terbinafine, Itraconazole, Fluconazole are all oral medication options for treating this condition. Terbinafine is perhaps the most commonly prescribed and is useful against both dermatophyte and non-dermatophyte species. Itraconazole has greater effect toward non-dermatophyte species, however, it must be used in caution as it is contraindicated in pregnancy. Fluconazole is another option, however, therapeutic treatment times remain longer when compared to other oral medications. Furthermore, both mechanical and chemical debridement remain as options for treating onychomycosis. Chemical debridement often consists of applying a compound containing urea to the nail. Depending on the exact formulation of the compound, this may be done under occlusion or without occlusion. It should be noted that chemical debridement alone is not effective and often has to be combined with other treatment modalities. Lastly, mechanical debridement or avulsion of the nail plate remains a viable option especially in cases where previously mentioned treatment modalities have failed. However, care must be taken in patients with comorbidities such as peripheral vascular disease, diabetes, or infection.
Werner B, Antunes A. Microscopic examination of normal nail clippings. Dermatol Pract Concept. 2013;3(3):9-14. Published 2013 Jul 31.
Ranawaka RR, Nagahawatte A, Gunasekara TA. Fusarium onychomycosis: prevalence, clinical presentations, response to itraconazole and terbinafine pulse therapy, and 1-year follow up in nine cases. Int J Dermatol. 2015;54(11):1275-1282.
Rammlmair A, Muhlethaler K, Haneke E. Fusarium onychomycoses in Switzerland-A mycological and histopathological study. Mycoses. 2019;62(10):928-931.
Gupta AK, Simpson FC. New therapeutic options for onychomycosis. Expert Opin Pharmacother. 2012;13:1131-1142.
Gupta AK, Kohli Y. In vitro susceptibility testing of ciclopirox,terbinafine, ketoconazole and itraconazole against dermatophytes and nondermatophytes, and in vitro evaluation of combination antifungalactivity. Br J Dermatol. 2003;149:296-305.
Figueiredo VT, de Assis Santos D, Resende MA, et al. Identificationand in vitro antifungal susceptibility testing of 200 clinical isolates of Candida spp. responsible for fingernail infections. Mycopathologia. 2007;164:27-33.
Emam, Sherin, and Osama El-salam. “Real-Time PCR: a Rapid and Sensitive Method for Diagnosis of Dermatophyte Induced Onychomycosis, a Comparative Study.” Alexandria Journal of Medicine, 29 Aug. 2015.
D’Hue, Zandra, et al. “GMS Is Superior to PAS for Diagnosis of Onychomycosis.” Journal of Cutaneous Pathology, 14 Aug. 2007.
West, Kelly, et al. “Fontana-Masson Stain in Fungal Infections.” Dermatopathology, Dec. 2017.