The present invention includes a method for treating fungal infections, particularly onychomycosis. The method includes: applying a composition includes a photosensitizer, an effective amount of antifungal agent, and a pharmaceutically acceptable delivery system to a locus and irradiating the locus with a light source at a wavelength absorbed by the photosensitizer so as to destroy microbes at the locus. The present invention also includes a light delivery device for use in photodynamic treatment of onychomycosis comprising (i) a housing adapted to cover a nail beneath which a locus is situated; (ii) a light source; (iii) an energy source in power communication to the light source; and a controller that controls amount of light to be applied to the locus by the light source.