Medical expert of the article
New publications
Epidermophytosis pathogens
Last reviewed: 04.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
The causative agents of epidermophytosis are dermatophytes, or dermatomycetes. They cause trichophytosis, microsporia, favus and other lesions of the skin, nails and hair. Dermatophytes are divided into three genera: Microsporum, Trichophyton, Epidermophyton, representatives of which differ in the methods of sporulation.
Morphology and physiology of dermatophytes
Dermatophytes have septate mycelium with arthroconidia, macro- and microconidia. Fungi of the genus Epidermophyton have many smooth club-shaped macroconidia, and representatives of the genus Microsporum have thick-walled, multicellular, spindle-shaped microconidia with spines. Fungi of the genus Trichophyton are characterized by large smooth septate macroconidia. Fungi reproduce asexually (anamorphs) or sexually (teleomorphs). They grow on Sabouraud's medium and others. Colonies (depending on the species) are multi-colored, mealy, granular, fluffy.
Dermatophyte resistance
Fungi are resistant to drying and freezing. Trichophytons remain in hair for up to 4-7 years. Dermatophytes die at 100 °C after 10-20 minutes. They are sensitive to UV rays, alkali solutions, formaldehyde, iodine.
Pathogenesis and symptoms of epidermophytosis
Pathogens live on keratinized substrates (keratinophilic fungi). The development of the disease is facilitated by minor skin lesions, maceration, weakened immunity, increased sweating, endocrine disorders and long-term use of antibiotics. Dermatophytes do not penetrate beyond the basement membrane of the epidermis. Skin, hair and nails are affected to varying degrees. A distinction is made between dermatomycosis of the trunk, limbs, face, foot, hand, perineum, beard area, scalp, nails (onychomycosis).
Hair affected by fungi breaks off; focal alopecia and baldness develop. The skin peels, vesicles, pustules, and cracks appear. Itching of the affected areas develops. Inflammation is absent or may be pronounced. Fungal nail infections (onychomycosis) change the color, transparency, thickness, surface, strength, and integrity of the nail plate. Onychomycosis can be caused by any pathogen. The development of mycoses is facilitated by decreased immunity. People infected with fungi develop IgM and IgG antibodies, and DTH develops.
Epidemiology of athlete's foot
Pathogens are transmitted through contact with a sick person or animal or through contact with various objects in the environment. Infection is possible through household items (combs, towels), as well as in baths, showers and swimming pools.
Anthropophilic dermatophytes are transmitted from person to person. Zoophilic dermatophytes are transmitted to people from animals. Trichophyton verrucosum is transmitted from cattle (calf lichen). Geophilic dermatophytes (pathogens of microsporia) live in the soil and are transmitted by contact with it.
[ 7 ]
Microbiological diagnostics of epidermophytosis
Scrapings from the affected skin, scales, nail plates, hair treated for 10-15 minutes with a 10-15% KOH solution are examined under a microscope. The preparations are stained with hematoxylin and eosin. RIF with fluorescent antibodies can be used. Microscopy reveals mycelial threads, arthroconidia, macro- and microconidia, blastospores. Arthroconidia of the genus Trichophyton can be located in parallel chains outside the hair (ectothrix) and inside the hair (enlosrix). Arthroconidia of the genus Microspomm are located in a mosaic outside the hair. With favus, fungal elements and gas bubbles are found inside the hair.
They sow on nutrient media - Sabouraud and others. The growth of fungi is studied after 1-3 weeks of cultivation at 25 °C. Antibodies in the blood serum are determined using RSK, RIGA, RP, RIF, IFA. Skin-allergic tests with allergens from fungi are done. A biological test is done on laboratory animals (guinea pigs, mice, etc.), infecting their skin, hair and nails.
Treatment of epidermophytosis
For dermatophytosis of the scalp, fluconazole is used; for dermatophytosis of the nails, systemic and local antifungal therapy is carried out; for dermatophytosis of the feet, antifungal creams and ointments are used in combination with systemic therapy and antihistamines, if indicated.