Jock itch, medically known as tinea inguinalis, is a fungal infection of the groin area. Men are affected more often than women.
The infection is caused by filamentous fungi belonging to the dermatophyte family. The term “dermatophyte” combines the ancient Greek words for “skin” (derma) and “plant” (phyton). Dermatophytes live on the skin.
In medicine, the term “tinea” (Latin for “woodworm” or “moth”) refers to all dermatophytosis conditions:
- Tinea pedis refers to athlete’s foot,
- tinea manuum is a dermatophyte infection of the hands,
- tinea capitis refers to the infection of the scalp,
- and tinea inguinalis (from the Latin inguen, meaning “groin” or “lower abdomen”) is a fungal infection of the groin.
In addition to dermatophytoses, candidiasis is a common fungal infection of the skin. Unlike tinea, however, it is caused by yeast fungi.
In biological classification, fungi form their own kingdom alongside multicellular animals and plants. They are eukaryotes—that is, organisms whose cells, unlike those of bacteria, possess a cell nucleus. Based on the characteristics of their metabolism, fungi are more closely related to animals than to plants.
The fungal kingdom encompasses the entire spectrum from
- microscopically small single-celled organisms such as yeasts and
- multicellular organisms such as molds and fungi.
Fungi account for one-quarter of the Earth’s biomass. However, most fungal species remain largely invisible. Large fungi native to forests and meadows are in the minority.
A large proportion of fungal species live underground. As important symbionts, these fungi promote the growth of about 80 to 90 percent of all plants.
As beneficial organisms for humans, fungi enhance the flavor of food. Humans use fungi in various fermentation processes, such as in the production of alcoholic beverages and dairy products.
As pathogens, fungi colonize the skin or the body’s internal organs and can
- poisoning,
- allergies, or
- infections
. Dermatophytes are also harmful organisms.
Dermatophytes feed on carbohydrates and keratin. Keratin is a major component of the outermost layer of the skin, hair, and nails. This is why filamentous fungi particularly favor the surfaces of vertebrates as their preferred habitat.
Filamentous fungi are found everywhere in nature. In their spore stage, fungi are
- highly resistant to climate and weather,
- excellently protected against dehydration, and
- can survive for long periods without nutrients.
As a form of dormancy, they lie in wait in the soil or in damp, heavily frequented public spaces such as
- swimming pools,
- showers,
- saunas, or
- hotel rooms.
Fungi can spread
easily in swimming pools © yanlev | AdobeStock
In addition, they tend to thrive on
- clothing,
- towels,
- combs,
- blankets, and
- doormats
. In this environment, they remain infectious for up to four years.
Within the dermatophyte family, Trichophyton rubrum is the most common cause of jock itch. Other fungal species include
- Epidermophyton floccosum,
- Trichophyton mentagrophytes, and
- Trichophyton tonsurans
may also be responsible for jock itch.
Skin fungi find ideal growing conditions in warm, moist, and dark environments. They thrive in skin folds and on the feet inside tight, airtight, closed shoes.
The pathogens reach the feet and nails when walking barefoot in environments conducive to fungal growth, such as swimming pools and saunas. This is why athlete’s foot and toenail fungus are much more common than jock itch.
However, a foot fungus infection that is detected too late or not treated as prescribed can eventually spread to the groin area.
Whether dermatophytes can spread to the groin area depends to a large extent on
- overall physical condition,
- individual lifestyle habits, and
- personal hygiene and health awareness
. A number of general factors are known to promote the development of jock itch.
Healthy skin is protected by its natural skin flora. A multitude of beneficial microorganisms colonize the skin’s surface and perform a defensive function. In addition, the skin is covered by a dense stratum corneum that is impermeable to germs.
The carefully balanced interplay of these various protective mechanisms is sensitive to disruption. Diseases that affect the immune system, as well as improper skin care, can reduce the skin’s ability to defend itself. This allows fungal pathogens to penetrate the skin.
- Diabetes mellitus is among the chronic conditions that affect the immune system. Poorly controlled diabetes increases susceptibility to bacteria and fungi. As a result, fungal infections tend to spread primarily in the lower extremities.
- Circulatory disorders in the outer regions of the body, such as peripheral arterial occlusive disease, impair the immune system and the skin’s ability to regenerate. This creates favorable conditions for fungi, which often lead to fungal infections of the feet.
- Severe obesity (adiposity) can create microclimates within skin folds where dermatophytes thrive.
- Cortisone or certain medications—such as those used during cancer treatment—suppress the immune system. This allows fungal pathogens to become more active.
- Unsanitary toilet seats, inadequately washed laundry, and intimate physical contact promote the transmission of fungal pathogens.
Tinea inguinalis initially presents as red patches on one or both inner thighs.
As the condition progresses, the edges of the affected skin areas appear slightly inflamed and scaly. The center gradually fades and takes on a brownish color. Jock itch is accompanied by itching, and those affected often complain of a burning sensation.
If the growth of the fungus is not controlled, jock itch can spread further. In such cases, large areas of skin on the outer part of the genital region, extending all the way to the buttocks, may also be affected.
Jock itch tends to develop in dark, warm, and moist skin folds © timonina | AdobeStock
All fungal infections should be treated promptly and thoroughly. However, this requires the precise identification of the pathogen. Consult your doctor, especially if
- you are pregnant—during pregnancy, any medical intervention must be evaluated by a doctor
- you are experiencing unclear symptoms that do not definitively point to tinea inguinalis
- you suspect you have a fungal infection but are unfamiliar with its typical course from personal experience
- self-treatment with a typically effective medication is not helping
- you have been suffering from jock itch and other extensive fungal infections of the skin and nails for an extended period of time. In this case, it must be determined whether a genetic predisposition is causing the development of Trichophyton rubrum syndrome. This is associated with persistent and protracted courses of infection.
If the doctor suspects a fungal infection, they will typically confirm the diagnosis by identifying the pathogen.
A swab of the affected tissue collects skin particles, which are used to prepare a culture in the laboratory. Fungal pathogens present in the sample are cultured on special media and later examined under a microscope. Depending on the fungus’s growth rate, a culture takes between one and four weeks to develop. Only then can a diagnosis be made.
A laboratory-based differential diagnosis
- distinguishes a fungal infection from bacterial infections
- distinguishes tinea inguinalis from psoriasis, which causes similar symptoms
- provides information about exactly which fungal pathogens are involved in the disease process.
Based on the results of the pathogen detection, the doctor decides on the next steps in treatment. The doctor determines
- which active ingredient is best suited to treat the infection,
- whether local treatment is sufficient, or
- whether you need to take additional antifungal medications (systemic therapy).
Once a diagnosis of tinea inguinalis has been confirmed, self-treatment with a topically applied antifungal medication usually follows. Among the proven medications are those containing the active ingredient bifonazole.
Treatment of the fungal pathogen leads to a reliable cure when a broad-spectrum antifungal is used. Bifonazole is a drug belonging to the azole class. It has both fungistatic and fungicidal effects. This means that it both inhibits the growth of the fungal pathogens and destroys them. Bifonazole also has anti-inflammatory properties.
The best option is a cream that
- comprehensively combats the fungal infection and is equally effective against dermatophytes, yeasts, and molds
- stops the growth of the fungus by damaging the structure of its cell membrane, thereby killing the pathogen
- is effective against bacterial pathogens that cause additional damage to the skin at the site of the fungal infection
- has anti-inflammatory properties and quickly relieves symptoms associated with tinea inguinalis, such as itching and burning.
Waterproof creams are particularly suitable, as they remain effective even during sports and leisure activities.
The success of treatment depends crucially on consistent adherence to the regimen. Do not stop using the antifungal medication prematurely, even if your symptoms subside quickly.
An antifungal medication usually needs to be applied for two to three weeks after the infection has cleared up. This is the only way to ensure that the pathogens are permanently eliminated and that the fungal infection does not flare up again.
Be sure to follow the instructions for dosage and use. If you have any questions, ask a doctor or pharmacist.
