Ringworm: Information & Ringworm Specialists

Ringworm is medically referred to as tinea corporis and is also known as a fungal infection of the body. It is caused by certain fungi, known as dermatophytes. These fungal pathogens break down human keratin, which is an important component of nails, hair, and the stratum corneum.

Dermatophytes are extremely resistant to drying out. There are a total of 40 different species. In Central Europe, Trichophyton rubrum is the most common strain of dermatophyte.

In children and adolescents, zoophilic dermatophytes are the primary cause of ringworm. These are pathogens that are mainly transmitted by pets such as

• hamsters,
• mice,
• rabbits,
• guinea pigs, or
• rats

.

After entering the human body, dermatophytes spread around the site of entry, where they cause inflammation. Inflammation caused by zoophilic dermatophytes is usually more severe.

Tinea corporis is one of the most common skin diseases of all. The percentage prevalence of the individual dermatophytes is as follows:

• T. rubrum: 66 percent
• M. canis: 12 percent
• T. tonsurans: 9 percent
• T. mentagrophytes: 8 percent
• T. verrucosum: 2 percent
• Epidermophyton floccosum: 2 percent

Factors that increase the risk of infection with this skin fungus include a warm, moist environment on the skin, such as

• after swimming, 
• sweating during physical labor, or
• a generally warm, humid climate.

Other risk factors include

• diabetes mellitus,
• a weakened immune system (for example, due to immunodeficiencies, immunosuppressive medications, or HIV),
• circulatory disorders of the skin, or
• excess weight (obesity).

In addition, tinea versicolor occurs much more frequently in cases of pathological skin sensitivity. An example of such skin sensitivity would be atopic dermatitis.

Furthermore, older adults and children are more frequently affected by tinea corporis.

Typical symptoms of tinea corporis include circular lesions with well-defined borders and

• scaling,
• redness,
• small papules, and
• sometimes small pustules.

The center of the circular lesions is usually pale. Affected individuals experience itching at these sites. The well-defined border helps distinguish tinea corporis from eczema. In eczema, the most severe changes are always found in the center and become less pronounced toward the edge.

The lesions slowly expand outward—often over the course of weeks—toward the periphery. New lesions also repeatedly develop.

However, the infection can also run deeper. In such cases, very severe inflammatory reactions are triggered. These include

• extremely painful and weeping nodules and
• swollen lymph nodes in the affected area.

Furthermore, patients suffer from fatigue and fever. The severe inflammation indicates that this fungus is not well adapted to humans. The animals themselves often show only very subtle signs of the disease.

If ringworm remains untreated for too long, it can become chronic. It is also possible for others to become infected.

People with weakened immune systems face an additional risk. In such cases, tinea corporis can also affect internal organs.

Ringworm on a man’s armpit © RandomizeTH | AdobeStock

Symptoms such as skin irritation, redness, and itching can also occur with other conditions. Therefore, a doctor should determine the cause of these symptoms.

Conditions with similar symptoms include, for example:

• Seborrheic and nummular eczema
• Pityriasis rosea (a skin condition characterized by scaling and redness)
• Psoriasis
• Pityriasis versicolor (tinea versicolor)

The doctor will first conduct a thorough examination of the skin. Using a swab, the doctor collects infected material, which is then examined under a microscope. If there is strong clinical suspicion, a fluorescent dye may also be added to facilitate or improve the diagnosis.

To determine the exact genus and species of the pathogen, a fungal culture is prepared. The cells collected via the swab are grown on a special culture medium. Depending on the pathogen, this can take about three to six weeks.

Accurate identification of the pathogen is essential for

• systemic therapy tailored to it, as well as
• identifying chains of infection

.

In some cases, additional tests may be necessary. These include, among others:

• Examinations using a Wood’s lamp. This is a lamp that emits UVA rays with a wavelength of up to 365 nm (so-called black light). This allows for the detection of specific species of dermatophytes. If tinea corporis is present, the affected areas appear yellow-green under this light.
• Culturing samples to classify the pathogens.
• Sometimes it is also necessary to test patients’ tolerance to specific antifungal medications.
• Use of DTM medium to differentiate between molds and dermatophytes.
• Differentiation of dermatophyte strains using genetic testing. This is only necessary when conventional methods are insufficient.

An accurate diagnosis is essential for successful treatment. The diagnostic data are crucial for selecting the appropriate antifungal medication.

Topical treatment of tinea corporis

Treatment typically involves a local, externally applied regimen, known as topical therapy. Antifungal agents are applied directly to the affected areas of skin.

Recognized classes of active ingredients include:

• Azoles: miconazole, clotrimazole, bifonazole, econazole, sertaconazole, and tioconazole
• Hydroxypyridones: ciclopirox olamine
• Allylamines: terbinafine, naftifine
• Morpholines: amorolfine

Depending on the severity and location, these medications are available as

• solutions,
• gel,
• cream,
• powder, or
• paste

. The range of applications varies among the different formulations.

Most classes of active ingredients inhibit ergosterol biosynthesis in the fungal cell membrane. Ergosterol is a component of the so-called cytoplasmic membrane. Inhibiting biosynthesis significantly impairs the membrane’s function. This effectively curbs the growth and reproduction of the pathogens.

If treatment is discontinued immediately after the symptoms disappear, recurrences may occur. This means that the inflammation can flare up again because the pathogens have not been eliminated. Treatment must therefore be continued for up to three or four weeks after clinical resolution.

Systemic Treatment of Tinea Corporis

In most cases, topical therapy is sufficient. However, sometimes it is ineffective, or the tinea corporis is too widespread. In such cases, systemic therapy is prescribed. The patient takes medications that act throughout the entire body rather than just locally.

In systemic therapy,

• the patient’s age, as well as
• in children, body weight, and
• possible interactions with other medications

play a role.

The following medications are used for this form of treatment:

• Micronized griseofulvin
• Azoles: itraconazole
• Allylamine: Terbinafine

Treatment is usually provided on an outpatient basis. In some cases, inpatient treatment may be necessary, particularly for severe forms of the disease.

Especially in children, systemic therapy should always be combined with topical therapy. This ensures immediate effectiveness and prevents the spread or transmission of the infection. Imidazole and azole derivatives are primarily used for this purpose in children.

Tinea corporis usually has a very favorable prognosis. After successful treatment, the areas of inflammation heal without leaving any scars. However, if the infection is left untreated, it becomes chronic.

For a long time, griseofulvin was the only approved medication for the systemic treatment of children and adolescents. Compared to other antifungal agents, however, its efficacy is considerably lower. In such cases, an increased dosage of up to 25 mg/kg body weight per day is recommended. Depending on the pathogen, the duration of treatment ranges from two to eight weeks.

In addition to griseofulvin, fluconazole is also suitable for treating patients one year of age and older. One drawback, however, is its interaction with various other medications.

Treatment During Pregnancy and Breastfeeding

Clotrimazole can be used for the topical treatment of dermatophytes during pregnancy and breastfeeding. Other antifungal medications are not recommended during this time, as there are no definitive studies on their use.

If there is a compelling medical need for another active ingredient during breastfeeding, it should only be

• applied to small areas and
• temporarily

. Systemic therapy during pregnancy should only be used in life-threatening situations.

Systemic antifungals are also not recommended during breastfeeding. Azoles can pass into breast milk.

If systemic therapy is unavoidable during this time, fluconazole is the drug of choice. It has a relatively favorable side effect profile. All other systemic antifungals should be avoided during breastfeeding.

Dermatophytes thrive in moist areas of the skin. Therefore, you should keep your body as dry as possible.

Especially after swimming, it is recommended to change out of wet swimwear immediately. Sweaty skin is also an ideal breeding ground for fungi. For this reason, you should always carry a change of clothes with you in the summer or wear breathable clothing.

In addition, clothing, pillowcases, and blankets should be washed at 90 degrees. This kills the pathogens and prevents reinfection with ringworm. Items such as combs or brushes can also be sprayed with antifungal disinfectants.

If you suspect ringworm, you should take action as soon as possible. Otherwise, it is very difficult to take preventive measures. The fungal pathogens are often transmitted from animals to humans, and animals show hardly any symptoms when infected.