Type of Toenail Fungal Infection

Toenail fungus is categorized into 4 major groups depending on its location on the toenail:

Distal Subungual Onychomycosis – DSO

DSO is the most common type of toenail fungus (Onychomycosis) which affects either distal or lateral nail bed and may progress to the nail plate. This type of toenail fungus is caused by an organism called Trichophyton Rubrum. In DSO, infection starts from hyponychium and progress proximally. Infected area of the nails changes its color to white, yellow and green. Accumulation of hyperkeratotic debris under the nails may cause the infected nail to detach from the underlying skin

White Superficial Onychomycosis – WSO

About 10% of all the toenail fungal infections fall into this group. It is not as common as DSO. The major causes of WSO is Trichophyton mentagrophytes. These organisms invades the outer layer of the nail plate and create several white patches on the nail plate. As the infection progress, these areas join together and cover all the nail plate. That is why this type of toenail fungus is called, White Superficial Onychomycosis. The nail is not detached from the underlying skin in the early stages of disease.

Proximal Subungual Onychomycosis – PSO

PSO is the least common and the rarest type of onychomycosis. It is usually caused by a fungus called Trichophyton rubrum. The fungus invades the nail plate via proximal nail fold and progresses distally. It manifest as a white or yellowish spots in the cuticle area of the toenail. In the early stages of the infection, the fungus involves the superficial layers of the nail and if left untreated it will also infect the deeper layers of the nail plate.