Proximal white subungual onychomycosis in the immunocompetent patient: report of two cases and review of the literature.

Sir, Proximal white subungual onychomycosis (PWSO) is the rarest subtype of onychomycosis (1). In PWSO, the infection begins with fungal invasion of the stratum corneum of the proximal nail fold, followed by infection of the deeper portions of the nail plate. This presentation of onychomycosis is most commonly caused by T. rubrum; other common causative agents include T. megninii, T. schoenleinii, T. tonsurans, T. mentagrophytes, and E. £occosum (1, 2). The majority of initial cases of PWSO reported were patients with AIDS (1 ^ 3). In one study, 55 of 62 HIV-infected patients with onychomycosis (83.7%) had PWSO (4). In more than half of these patients (58%), T. rubrum was the etiologic agent. PWSO has also been reported in patients with other immunode¢ciencies, including a renal transplant recipient on immunosuppressive therapy (5), and a patient with systemic lupus erythematosus on systemic steroids (6). In addition, Baran (7) described a case of proximal subungual candida onychomycosis as a manifestation of chronic mucocutaneous candidiasis. Recently, however, there have been several reports of immunocompetent patients developing PWSO (8 ^ 10). We now report two immunocompetent patients with proximal white subungual disease, and review the other cases described, emphasizing that not all patients with this presentation are immunode¢cient.