Dermatophytoses: what they are, main types and how is the diagnosis

Dermatophytoses, also known as superficial mycoses or ringworms, are diseases caused by fungi that have an affinity for keratin and, therefore, reach places where there is a higher concentration of this protein, such as skin, hair, hair and nails.

Dermatophytoses can be caused by dermatophyte fungi, yeasts and non-dermatophyte filamentous fungi, less frequently, which are those that have no affinity for keratin. Dermatophyte fungi can be classified according to the places where they are found naturally in:

• Anthropophiles, which are found naturally in people and can be easily transmitted from person to person; Zoophilics, which are found in animals; Geophilic, whose natural habitat is the soil. Geophilic species cause a more extensive reaction of the immune system and, therefore, there is the formation of lesions that are more difficult to be treated.

The transmission of dermatophytoses occurs through contact with contaminated animals, people or objects, contact with the soil where there is fungal growth and through the inhalation of fragments of keratin containing the fungus that are suspended in the air.

The development of superficial mycoses is more common in people whose activity or health status favors the contact or proliferation of fungi, such as farmers, athletes, diabetics, people with compromised immune systems and people who work with glove and with cleaning products.

Main dermatophytoses

Dermatophytoses are popularly called ringworms or tineas and can be located in different areas of the body, being, therefore, named according to their location. Ringworms promote the appearance of signs and symptoms according to where they occur and usually heal on their own or tend to chronicity. The main dermatophytoses are:

1. Tinea pedis

Tinea pedis corresponds to the ringworm that affects the feet and can be caused by the fungi Thichophyton rubrum and Trichophyton mentagophytes interdigitale . Tinea pedis is popularly known as chilblains or athlete's foot, as it is more common in sports practitioners who often wear closed shoes with socks, who frequent humid public places, such as bathrooms and swimming pools, since fungi develop more easily in this type of environment.

The main indicative sign of athlete's foot is itching between the toes, flaking and whitening of the area, as well as a bad smell. The treatment for tinea pedis is simple, and should be done with the use of antifungal ointments for the period recommended by the doctor, in addition to being indicated to avoid staying for a long time in shoes and wearing sandals in public places with humidity. Learn how to identify and treat tinea pedis.

2. Tinea capitis

Tinea capitis corresponds to ringworm that occurs on the scalp and can be caused by Trichophyton tonsurans and Trichophyton schoenleinii , which cause different clinical manifestations.

Trichophyton tonsurans is responsible for tinea tonsurant, which is characterized by the appearance of small dry alopecia plaques, that is, regions of the scalp without hair. Tonsurant tinea can also be caused by Microsporum audouinii , which leads to the formation of large alopecia plaques that fluoresce under Wood's lamp.

Trichophyton schoenleinii is responsible for tinea favosa, which is characterized by the formation of large whitish plaques on the head, similar to crusts.

3. Tinea cruris

Tinea cruris corresponds to the mycosis of the groin region, the inner part of the thighs and buttocks and is caused mainly by the Trichophyton rubrum . This ringworm is also known as ringworm of glabrous skin, since it affects regions where there is no hair.

These regions are usually covered most of the day, making them favorable to fungal growth and proliferation and leading to the appearance of signs and symptoms that can be quite uncomfortable, such as itchiness in the region, local redness and irritation.

4. Tinea corporis

Tinea corporis is the superficial ringworm of the skin and the fungi that are most frequently associated with this type of ringworm are Trichophyton rubrum, Microsporum canis, Trichophyton verrucosum and Microsporum gypseum. The clinical characteristics of tinea corporis vary according to the fungus, however the most characteristic signs are spots with red outline on the skin, with or without relief, itching in the region, with or without peeling.

5. Onychia

Onychia is the dermatophytosis that affects the nails and is usually caused by Trichophyton rubrum , which causes changes in the color, shape and thickness of the nails. See how to identify and treat nail ringworm.

Diagnosis of dermatophytoses

The diagnosis of dermatophytosis is based on the characteristics of the lesions caused by the fungi and laboratory tests. Only the evaluation of the lesions is not enough, since the signs and symptoms can be confused with other diseases.

Thus, it is recommended that microscopic analysis of samples from the affected site be performed, that is, samples of skin, hair and nails, for example, should be collected. These samples are sent to the specialized laboratory for analysis.

The classic diagnosis of dermatophytoses corresponds to a direct examination, in which the samples are observed under a microscope as soon as they arrive at the laboratory, followed by a cultural examination, in which the collected sample is placed in an appropriate culture medium so that there is growth and other ones can be observed. characteristics. Thus, the identification of the fungus is based on the growth rate and micro and macroscopic characteristics of the colony, such as surface, texture, pigmentation, shape and consistency. In some cases, it may be necessary to carry out complementary biochemical tests to confirm the diagnosis.

The laboratory exam to identify dermatophytoses takes about 1 to 4 weeks to be released, because it depends on the characteristics of the fungi. Some fungi can take weeks to grow and there is enough material for proper diagnosis and analysis. Despite the time required for diagnosis, this is the best way to identify superficial mycoses.

One of the complementary tests that can be performed is the Wood Lamp, in which a low-wavelength UV light is applied to the affected region to check for fluorescence emission, since some fungi react in the presence of light, allowing the identification. One of the fungi most associated with fluorescence is Microsporum sp., Which can be found in hair, especially skin and nails, less frequently. Understand what the Wood Lamp is for and how it works.

How the treatment is done

In most cases, the treatment of dermatophytoses is topical, that is, the doctor can only recommend the application of ointments or creams containing antifungal. However, in the case of more extensive lesions or in the case of ringworm on the nail or scalp, it may also be necessary to use oral antifungals.

The most suitable medication for the treatment of dermatophytosis is Terbinafine and Griseofulvin, which should be used as directed by the doctor and Griseofulvin should not be used in children.

Home treatment

There are some plants that can help treat dermatophytosis and relieve itching, because they contain antifungal and healing properties. The plants that can be used to prepare home remedies for ringworm of the skin are sage, cassava, aloe vera and tea tree, for example. See how to prepare these home remedies.