Mycoses are infections caused by some types of microscopic fungi that can be formed by a single cell (unicellular) and have an ovoid shape (yeasts) or be composed of several cells (multicellular) and be filamentous (molds and dermatophyte fungi). Most fungi are commonly found in the environment (soil, air) or on the skin and mucous membranes (mucosa of the intestine, vagina and mouth). Many of them live with humans without causing any harm (commensalism) but, under certain circumstances, they can cause disease.
Most mycoses are transmitted to humans from the external environment, either by direct contact between people or by indirect contact with infected materials. They can also be transmitted from animals (dogs, cats, cattle) or from the soil.
Some mycoses have endogenous origin, ie they are caused by fungi normally present in the upper respiratory tract, on the skin or on the mucous membranes; in this case, the transition from the phase of coexistence without damage (commensalism) to that of illness is caused by predisposing factors of different types.
An "important distinction must be made between infections that can affect healthy people and those, so-called opportunistic, that develop exclusively in people with a weakened defense system."
Mycoses can have different localizations: superficial, subcutaneous and deep.
In the superficial mycoses Fungal infection is limited to the surface of the skin, hair and dander, nails or mucous membranes. They are the most common fungal diseases and are generally not serious. They include:
- mycosis of the nails (onychomycosis)
- mycosis of the skin and hair / hair (tigne, athlete's foot)
- pityriasis versicolor
- mucocutaneous candidiasis (candidiasis of the skin and mouth, throat and esophagus, Candida vulvovaginitis and balanitis)
In the subcutaneous mycosis Infection involves the deeper layers of the skin, subcutaneous tissue and muscles. Very rare in Europe, they are difficult to ascertain (diagnose). They include:
In the deep mycosis the fungal infection affects the internal organs (lungs, heart, bloodstream, brain, etc.). They are uncommon (some very rare), but they are serious and often very dangerous, at times they can be fatal. Many of them are opportunistic infections and occur almost exclusively in individuals whose immune systems are severely compromised or in people hospitalized for serious illness. They include:
- disseminated candidiasis
- histoplasmosis, blastomycosis and coccidioidomycosis
- fungal keratitis
In general, the most common mycoses are those of the nails (onychomycosis), skin and hair / hair (ringworm, athlete's foot).
The disorders (symptoms) caused by mycoses are different according to their location and type.
Mycosis of the nails (onychomycosis)
Fungus can affect both fingernails and toenails and can affect one or more nails at the same time.
In the beginning, mycosis of the nails causes a change of color and appearance of the infected nail, in particular of its extremity which can become yellowish, with brown, green or black spots. The surface of the nail also appears more fragile, brittle, deformed and thick.
If the infection progresses, the nails may crumble sideways causing pain or even detach or become infected with bacteria that cause inflammation.
Mycosis of the skin and hair / hair (ringworm, athlete's foot)
These diseases are commonly called ringworm (in Latin tinea) and are located in different parts of the body:
- face, neck, trunk, arms or legs (tinea corporis)
- inguinal folds, inner thighs, buttocks (tinea cruris)
- scalp (tinea capitis)
- beard (tinea barbae)
- feet (tinea pedis or athlete's foot)
The infection generally manifests itself with circular spots, with more or less sharp edges, red, itchy and sometimes scaly. tinea capitis and barbae, hair loss and hair loss appear in the affected area. They are very common and not serious, but they are very contagious.
The disorders (symptoms) depend on the part of the body infected and appear between 4 and 21 days from contact with the fungus that is responsible for it.
There tinea corporis it manifests itself with one or more spots on the skin, initially punctate and then ring-shaped, which appear red, have clear and sometimes raised edges and cause itching. The spots are contagious and spread at a distance, by self-contagion caused by scratching, giving rise to new spots smaller than the initial ones. The areas not covered by clothing are those where the first lesion most commonly appears (neck, face, hands, forearm). It is more common in children.
There tinea cruris it manifests itself with reddened and desquamated spots, especially at the edge, localized to the groin. The spots usually appear on both sides and are severely itchy. Hair is never infected. The disease tends to progress to the inner thighs, abdominal region, perineum and buttocks. It is more common in males.
There tinea capitis it mainly affects children. The most frequent form is the tinea capitis microsporica (caused by the fungus Microsporum canis) which manifests itself with one or more rounded patches with sharp edges, with reddened and abundantly flaking skin (the hair seems floured) and with hair clipped 3-4 millimeters from the root.
There tinea capitis ringworm (caused by fungi of the genus Trichophyton) presents with numerous patches of small diameter, with indistinct limits, minimally inflamed and with broken hair below the opening of the follicle (so-called black points).
There fabulous ringworm (responsible agent Trichophyton schoenleinii) causes scaly and red patches and the gradual appearance of yellowish foul-smelling crusts from which some dull and dusty hair may come out, thinning and breaking a few centimeters from the surface of the scalp. This type of ringworm causes destruction of the hair bulbs and can cause permanent baldness in infected areas.
There tinea barbae affects the beard and mustache area in adult males. In the superficial type, the lesions are similar to those of the tinea corporis with the central part desquamated in a more or less intense way and edge with vesicles. The deep type is the most frequent and is characterized by marked inflammation and the formation of red, pus-filled pustules and nodules.
In the tinea pedis (athlete's foot) the skin between the toes (commonly between the little toe and the adjacent toe) appears red, swollen and flaky and causes itching.The sole of the foot and the heel can also be affected and, in severe cases, blisters can form.
The causes that can cause the different types of mycosis can be divided into three groups:
- mushrooms proper
Normally, we tend to talk generically about fungal infections by understanding them all but the culprits can be different, some more frequent than others. Fungal infections that develop on the fingernails and toenails, skin and hair / dander are caused by fungi called dermatophytes (Trichophyton, Epidermophyton, Microsporum) or, more rarely, from yeasts (Candida) o molds (Aspergillus). These fungi are specialized in feeding on keratin, the protein of which the nails, the stratum corneum of the epidermis, the hairs and the hair are mainly made up.
Infection occurs by contact with infected people or animals but dermatophyte fungi are also present in the environment, especially in humid places. The tigne, in particular, they are very contagious and can also spread through the use of clothing, towels, sheets, combs or brushes, or through contact with carpets, floors, shower trays, sofas and armchairs contaminated with skin scales or human hair / infected animals. It is also common to spread the infection to other parts of the body by self-contagion through scratching or poor hygiene.
The risk factors that favor the spread of mycoses are:
- high humidity of the skin from sweating, with alteration of the degree of acidity / basicity of the skin (pH)
- excessive use of detergents, which induces a loss of the protective film naturally present on the skin and alters its pH
- poor hygiene
- prolonged therapies with cortisones, which can lower and alter the body's natural defenses
Any appearance of more or less permanent skin spots that raises the suspicion of mycosis requires a quick specialist visit to the dermatologist. The assessment of mycosis (diagnosis) is based on the observation of the infected areas (nails, skin, hair, hair) and on the analysis of the disorders (symptoms). Fragments of nails, hair, hair or skin can also be observed under the microscope , to verify the presence of fungal cells, or inserted in specific substances (culture media) that favor the multiplication of fungi and allow to ascertain exactly which species it is. In the case of the most serious infections, a histological examination of the parts of epidermis taken.
The treatment of mycosis consists of antifungal drugs to be applied locally, in the form of gels, powders or creams, or to be taken by mouth (orally).
The mycosis of the nails (onychomycosis) are not easy to eliminate and do not heal if you do not intervene with special antifungal drugs (antifungals), both for local use (enamels or ointments) and general (oral antifungals). The most used active ingredients are chlortrimazole, miconazole, terbinafine or ketoconazole. The pharmacological treatment of this type of mycosis is very long because the nail takes from several months to a year to regrow completely. Only in very serious cases the doctor may recommend the complete removal of the nail.
The care of tigne depends on the type and severity of the infection.
Tinea pedis And tinea cruris in a mild or widespread form, they can be treated with the local application, for 2-4 weeks, of antifungal creams, lotions, or powders (including over-the-counter drugs). If the infection does not heal or worsens it is necessary to consult your doctor to check the need for oral therapy.
Tinea capitis And barbaeinstead, they require a medical prescription for "adequate therapy with oral antifungals (griseofulvin, terbinafine, itraconazole or fluconazole) because in these forms the drugs for local use are not effective. Mouth therapy usually goes on for a long time (1-3 months).
There are several precautions to follow to prevent the different types of mycosis. In the first place, the creation of a favorable environment for the proliferation of fungal spores on the skin and mucous membranes should be avoided. It is necessary to practice constant hygiene but neither excessive nor too aggressive; the excessive use of products can damage the natural hydrolipidic film placed to protect the skin, thus favoring the rooting of fungi from infected environments, people or animals.
The mycosis of the nails (onychomycosis) and the tigne they are contagious.
For the tigne you should avoid using other people's sheets, towels, combs or brushes.
For the onychomycosis and athlete's foot avoid sharing personal items, such as nail clippers and scissors, with other people. If you turn to professionals for manicures or pedicures, you must check that the tools they use are sterilized after each use. In addition, the excessive and prolonged use of sports shoes that retain moisture without promoting evaporation should be avoided. It is certainly better to use shoes made of natural materials such as leather and cotton, perhaps together with antiperspirant powders. feet and hands, avoid cutting the nails too short, nibbling them, tearing cuticles: these lesions, however small, are privileged access doors for spores. Even the use of too tight trousers can increase the moisture in the genital areas, promoting the ideal environment for an infection.
Other precautions to be observed to avoid fungal infections include:
- wash your hands thoroughly with soap and water, after touching animals
- do not walk barefoot, in swimming pools, bathrooms, showers, changing rooms or public places, but always wear slippers (or other protections)
- check the health of pets, in case of suspected fungal infection consult your veterinarian
- take a shower immediately after playing contact sports, both in the event of training and competition, and keep sports clothing and equipment clean
- use antifungal powder in shoes, to prevent tinea pedis from returning after healing
If you live with a person or animal affected by mycosis it is advisable to:
- disinfect toilet items, linens, sheets, towels, clothing of the infected person and animal beds, using specific chemical products (bleach, benzalkonium chloride), high temperature washing with common detergents, ironing with a very hot iron, steam cleaning
- vacuuming often, to remove skin scales and infected hair
- disinfect floors and surfaces
- always use gloves and long-sleeved clothing, to handle an infected animal and wash your hands immediately afterwards
- check yourself often, to check that there are no spots or signs of possible infection
A correct and healthy diet, especially in obese people and / or with diabetes, helps to maintain a good balance of the intestinal flora, keeping the body's natural defenses high.
Mycosis must always be treated quickly, living with it is not recommended because the infection can spread to deeper layers of the dermis, can spread to other parts of the body and can infect other people or animals. In the case of people with diabetes, obese or immunosuppressed (due to AIDS or radio-chemotherapy treatments), the lack of therapeutic intervention can make them even worse.
Study Committee for Mycology (CoSM). Diagnostic path: Deep and systemic mycoses. Diagnostic path presented during the AMCLI National Congress. Rimini 18-21 October 2015
MedlinePlus. Mycosis fungoides (English)
Flevari A, Theodorakopoulou M, Velegraki A, Armaganidis A, Dimopoulos G. Treatment of invasive candidiasis in the elderly: a review. Clinical Interventions in Aging. 2013; 8: 1199- 1208