Mycotic Leukonychia in HIV Patients

Abstract

Onychomycosis is the fungal infection of the nail, that can be caused by dermatophytes, Candida sp. or non-dermatophyte moulds (NDM). The term tinea unguium is a specific form of onychomycosis caused only by dermatophytes and thus, should not be regarded as synonymous. (Odds et al., 1992) On the other hand, the term leukonychia or white nails has a varied etiology, it can be congenital or acquired, infectious and non-infectious. In the case of onychomycosis, the diseased nail plate has an external origin, which is the fungal invasion that affects secondarily the normally formed nail. This is also known as fungal or mycotic leukonychia (Baran et al. 1994). Onychomycosis, with all the different clinical presentations, is responsible for about 50% of all dystrophic nails and has a prevalence of 3-10% in the general population. Frequency also depends, on geographic conditions and age groups, with an increase in the prevalence in the elderly. It is now becoming more evident that immunosuppressed patients, particularly those living with HIV infection, are at a higher risk of presenting this nail fungal infection, and any clinical presentation is higher compared to the same age group of the general population ( Denning et al. 1995; Moreno-Coutino et al., 2011; Winberg et al. 2003). The first classification of onychomycosis was proposed by Zaias, and is based on the clinical appearance of the nails (Zaias, 1972). He described four clinical types: [1] distal subungual onychomycosis (DSO), [2] white superficial onychomycosis (WSO), [3] proximal subungual onychomycosis (PSO) and [4] Candida sp. onychomycosis. Since the publication of this paper, some modifications have been added. In 1998, Baran et al. proposed [I] distal and lateral subungual onychomycosis (DLSO), [II] superficial onychomycosis, [III] proximal subungual onychomycosis (PSO), [IV] endonyx onychomycosis and [V] total dystrophic onychomycosis (TDO). The most used these days is the following: DLSO, white superficial onychomycosis (WSO), PSO, Candida onychomycosis (paronychia) and TDO (Table 1) , (Baran et al 1998). WSO and PSO are also known as mycotic leukonychia. Further subdivisions are included in almost all the categories, and will be discussed further when necessary (Gupta & Summerbell, 1999). In 1976, English described a classification based on etiology, instead of the clinical aspect of the fungal invasion. The categories are: (a) dermatophytes causing tinea unguium, (b) moulds (Non-dermatophyte moulds [NDM]) and (c) yeasts (Crozier et al. 1979). At this moment, the