Nail Fungus Infection Types

Nail fungus (also known as nail mycosis or onychomycosis among medical professionals) is an infection of the fingernails or toenails. In the first step, it manifests itself in an abnormal discoloration of the nails. The disease of nail fungus is caused by an infection caused by the three different types of fungus filamentous fungus (dermatophytes), yeast or mold. The most common causes are the dermatophytes, which according to studies can be found in five to twelve percent of Europeans. There are four different types of nail fungus. These are listed below based on their decreasing severity:

  • Distolateral subungual onychomycosis (DLSO): The nail infection begins under the free nail in front or on the side and grows towards the nail root. Brittle, thick and milky spots develop on the nail plate, which have a white, yellow or brown color spectrum.
  • White superficial onychomycosis (WSO): Usually only found on toenails, small white spots appear on the nail plate that disintegrate easily.
  • Proximal subungual onychomycosis (PSO): The fungus grows under the cuticle and moves to the edge of the nail. A white discoloration occurs, but it is rarely destructive.
  • Endonyx onychomycosis (EO): There is a milky white discoloration, but no mechanical damage to the nail.

nail fungus infection types -

Distolateral Subungual Onychomycosis

Distolateral subungual onychomycosis, also called distal lateral onychomycosis, is a fungal infection of the nail and surrounding tissue. The thickening and discoloration of the nail and the loosening of the nail from the nail bed are characteristic of DLSO. The discoloration ranges from white to yellow to orange.

Toenails or fingernails are affected with nail fungus, also known as nail mycosis or onychomycosis. Causing pathogenic fungi are dermatophytes and molds, which can be assigned to the filamentous fungi or yeast fungi (sprouts). The infection can occur after an injury (trauma) to the nail and infects the (subungual) surface of the surrounding nail bed under the nail.

Mycoses of the nails were first detected by Virchow in 1854. As recently as 1992, the medical literature asked whether onychomycoses were curable infectious diseases. Significant advances have been made in the treatment of onychomycoses in the last few decades, and antimicrobial chemotherapeutic agents for systemic or topical use have shown excellent results.

Course of Distolateral Subungual Onychomycosis

The distal lateral subungual onychomycosis (DSO, DSLO) is the most common nail fungal disease and accounts for around 90 percent of all cases. Usually the hyponychium (the front area of ​​the finger on which the nail rests) and the distal parts of the lateral nail furrows are infected. As the infection progresses, it spreads to the nail bed and finally to the matrix.

Onychomycoses show white, gray, or yellow discoloration of the nails. The chronic fungal infection causes the nail to become dull, the nail plate thickens and ultimately destroyed by crumbling decay. Initially, there is often a loss of transparency of the nail and an increasing yellowish discoloration (dyschromasia). Subungual keratoses form, which lift the nail from the nail bed. In extreme cases, the nail dissolves (crumb nail).

Before subungual onychomycosis is noticed, the entire depth of the nail matrix and nail plate are almost always affected. In children, a single toenail is usually affected; in adults, both the big and little toes are most often affected. Fungal nail infections have no self-healing tendency. The infection always requires therapy. The specialist is the dermatologist.

WSO (White Superficial Onychomycosis)

One of the most common diseases of the nails is onychomycosis, the nail fungus. It comes in different forms. One of these fungal diseases is white superficial onychomycosis (WSO), which occurs on the nail surface and primarily affects the toenails. It is characterized by white spots on the top layers of the nail keratin. The risk of developing such a fungal nail infection increases with age. Like all fungal nail diseases, WSO can lead to a complete destruction of the nail. A proper nail substance can then no longer be formed.

Pathogens of WSO

White superficial onychomycosis is also known as leukonychia trichophytica because it is caused by trichophytes. The pathogens are mostly Trichophyton interdigitale, also known as Trichophyton mentagrophytes. This type of fungus belongs to the dermatophytes (thread fungi). Since the optimal growth of dermatophytes is at a temperature below 37 degrees Celsius, these fungi prefer the skin and its appendage organs. The dermatophytes have keratinases that digest human keratin. The WSO pathogen can therefore feed on human nails.

In this fungal disease, the fungal elements are only found in the upper layers of the nail keratin. This onychomycosis manifests itself with a rough, relatively soft and crumbly nail surface. The infected keratin is easy to scrape off your nails. White spots in the upper layers of the nail keratin are characteristic of this fungal nail disease. The whitish discoloration can occur selectively or affect the entire nail surface. The doctor can often tell from the clinical picture of the nails which onychomycosis is present. To get clarity about the pathogen, he can create a mushroom culture. In fungal culture, Trichophyton forms interdigital flat colonies that have a powdery, velvety surface.

The Course of WSO

If the white superficial onychomycosis is left untreated, the white spots on the nail surface can turn black or spread deeper. This depends on the spectrum of pathogens and the patient’s immune status. If the onychomycosis has existed for a long time, it can develop into total dystrophic onychomycosis (TDO). This is rather rare at WSO as this fungal disease affects the upper layers of the nail. TDO is the terminal stage of onychomycosis.

The entire nail is severely damaged in a TDO and can no longer form proper nail substance. The nail changes can represent a massive impairment of the quality of life for the patient. Onychomycosis is a cosmetic problem and can cause problems with nail care. It can lead to uncomfortable tenderness. Since the toenails are primarily affected, the nail fungus can cause problems when wearing shoes and walking.

PSO (Proximal Subungual Onychomycosis)

Onychomycosis is a fungal nail infection that can be caused by different types of fungus. The fungal infection is often caused by dermatophytes (thread fungi). Different types of onychomycoses are differentiated depending on the pathogen and the appearance. In proximal subungual onychomycosis (PSO), the infection occurs through the skin of the nail wall.

Pathogen and Spread of PSO

Proximal subungual onychomycosis is one of the rarer forms of onychomycosis. It is triggered by trichophytes, which belong to the group of dermatophytes. The causative agents of the proximal subungual onychomycosis are mostly Trichophyton rubrum or Trichophyton mentagrophytes or Trichophyton interdigitale. These dermatophytes find ideal growth conditions at a temperature of less than 37 degrees. They have the enzyme keratinase with which they can break down keratin. Keratin is a component of the nails. The nail substance is attacked by the nail fungus in PSO.

In proximal subungual onychomycosis, the infection occurs through the skin of the proximal nail wall, i.e. from where the nail grows out. The fungus spreads to the nail matrix via the cuticle on the underside of the nail (hyponychium) and infects it. The pathogen enters the nail plate from below and spreads further forward. This can destroy the entire nail.

Appearance of PSO

Proximal subungual onychomycosis almost always affects the toenails. It is noticeable with whitish or yellowish discoloration of the nails. The affected nails thicken and crumbly crumbly as the process progresses. Scaling can occur below the nail plate. The free end of the nail plate may lift off.

EO (Endonyx Onychomycosis)

Onychomycoses are fungal diseases of the nails. Frequent pathogens are dermatophytes (thread fungi), which have the enzyme keratinase and are able to destroy the nail component keratin. A rare form of onychomycosis is endonyx onychomycosis (EO), which develops within the nail plate. It is a particularly therapy-resistant form of nail fungus.

Pathogen / Appearance of Endonyx Onychomycosis

As with most types of onychomycosis, the pathogens causing endonyx onychomycosis are trichophytes, a type of dermatophyte. Endonyx onychomycosis is mostly caused by Trichophyton soudanense or Trichophyton violaceum. These pathogens only spread within the nail plate, while the nail surface and the nail bed remain intact. This fungal infection can be recognized by gray-yellow discolored, dull and opaque nails.

There may also be darker pigmentation on the affected nail. Since the nail surface is not damaged, there is no scaling on the surface of the nail in endonyx onychomycosis. As a result, endonyx onychomycosis, like other forms of onychomycosis, can develop into total dystrophic onychomycosis, which severely damages the entire nail organ. A proper nail substance can then no longer be formed.

Diagnosing EO

In order to diagnose endonyx onychomycosis, it is not enough to assess its external appearance. The doctor can rule out other diseases based on a blood test. To identify the pathogen, the doctor must take a sample of the infected nail and create a fungal culture.

Treatment of Endonyx Onychomycosis

Since endonyx onychomycosis is resistant to local and systemic antimycotics, the infected nail material must be removed a-traumatically. To do this, the diseased nail material is softened with urea with an active ingredient concentration of 40 percent. Careful removal of the material is required for long-term success of the treatment. Thereafter, treatment with topical antimycotics can be carried out in order to achieve lasting treatment success.

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