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The Four Types of Onychomycosis

Onychomycosis is the medical term for fungal infections that affect our nails. It accounts for about half of all conditions that affect the nails, and is the most common nail disease. Although it may be found on toenails or fingernails, it is much more commonly associated with the toenails, infecting up to 8 percent of the adult population. There are four main classifications of onychomycosis: distal subungual onychomycosis, white superficial onychomycosis, proximal subungual onychomycosis, and candidal onychomycosis. Three different pathogens are responsible for onychomycosis, including dermatophytes (fungi), nondermatophytic molds, and Candida. A doctor can accurately diagnose which type a patient may have through visual inspection and laboratory testing, and it is important to confirm the type so that the proper treatment method can be recommended.

The first and most common type of onychomycosis is distal subungual onychomycosis. It is usually caused by a dermatophyte called Trichophyton rubrum, which is a fungus capable of living in hair, skin, and nails. The infection typically begins under the nail at the edge closest to the tip of the toe or finger. It spreads across the entire nail and nail bed, causing a yellowing or other discoloration of the nail plate, thickening of the nail, brittleness and breakage, and separation of the nail from the nail bed. The jagged edges of the nail or thickness may cause pain while wearing shoes.

White superficial onychomycosis is caused by the dermatophyte Trichophyton mentagrophytes, and only accounts for a small percentage of fungal nail infections. This infection begins in the superficial layers of the nail, creating white, cloudy patches or speckles that may eventually invade the entire nail surface. As the fungus feeds on the keratin in the nail, it becomes soft, crumbling, and deformed. Lab tests will confirm the presence of this fungus so that treatment can be recommended.

The least common fungal type is proximal subungual onychomycosis, and is most frequently found in immunocompromised patients. This fungus initially invades the nail at the proximal nail fold, which is located near the cuticle where the newly formed nail plate emerges. The first signs of this infection are white or yellow discoloration of the nail, and eventually results in thickening and crumbling of the nail.

Candidal onychomycosis is caused by the pathogen Candida albicans, a diploid fungus related to yeast. It tends to develop in nails that are frequently exposed to water or have sustained prior trauma or injury. The early signs include a clouding of the nail surface, accompanied by pain and inflammation of the skin surrounding the nail. Left untreated, the skin may develop pus at the edge of the nail.

It is important to consult a physician if any changes are observed in the nails or surrounding areas. They may need to perform tests to accurately diagnose and treat fungal nail infections, as each type requires different methods of treatment.

If you suspect that you have onychomycosis, contact Total Foot Wellness at 800-808-1779 or fill out the consultation request on this site.