Proximal white subungual onychomycosis (PWSO) is a rare form of nail infection that occurs almost exclusively in immunocompromised patients. Initially, in several reports, PWSO was described in ARC and AIDS patients. Later this pattern of onychomycosis was observed in patients with renal transplants, who received immunosuppressive therapy, and recently in a woman with active systemic lupus erythematosus (SLE) treated with systemic steroid therapy. We report a case of recurrent PWSO in a woman affected by a defect of polymorphonuclear chemotaxis. The association between PWSO and a defect of neutrophil chemotaxis, not yet described in the literature, suggests a point of discussion about the role of polymorphonuclear leucocyte functions in the defense mechanisms of the host affected by dermatophytosis. In this report the close association between PWSO and an immunocompromised condition is once again described. For this reason the authors emphasize the importance of investigating the common and uncommon causes of immunodeficiency in all patients affected by PWSO.