Generality
Tinea cruris (or "jockey's itch") is a fungal infection that affects the surface layer of the skin of the inguino-crurale region .
This condition is supported by dermatophyte fungi, which mainly belong to the Trichophyton genus.
See Photo Tinea Cruris
Tinea cruris is more common in men than women and often appears during the summer season, after an abundant sweating episode. Infection is in fact favored by the establishment of a hot-humid microenvironment in the groin and in the crural region, which predisposes to the proliferation of pathogens.
The main risk factors for tinea cruris are the habit of wearing tight and not very breathable clothes, sports activity and the presence of concomitant dermatophytosis (often, the infection is contemporary with tinea pedis). Other predisposing conditions are obesity (responsible for the constant application of skin folds), diabetes and immunodeficiency states.
Tinea cruris shows a skin eruption, often bilateral, consisting of small round patches, reddened at the edges, which tend to flake; by enlarging peripherally, these lesions take on a characteristic ring-like appearance.
Another common symptom is itching, while pain can manifest itself when complications occur, such as maceration, intertrigo from Candida and bacterial superinfections caused by scratching.
Tinea cruris extends initially from the crural fold (ie near the root of the leg); from this site, the rash can spread to the inner surface of the thigh, the groin, the perineum and the perianal region.
The diagnosis is formulated on the basis of dermatological evaluation and microscopic, histological or cultural examination. In humans, the eruption of tinea cruris is well localized and does not tend to involve the scrotum and / or penis; these aspects are important to consider in the distinction of this infection from candidiasis.
The treatment of tinea cruris involves the use of antifungal drugs, to be applied locally to the skin or to be taken orally. To avoid relapses, therapy should be continued for a few weeks even after all signs of the disease have disappeared.
Causes
Tinea cruris is a superficial skin infection ( dermatophytosis ), located in the inguino-crurale region, usually due to fungi of the genus Trichophyton and Epidermophyton .
These microorganisms, called dermatophytes, are able to parasitize the stratum corneum of the epidermis and the cutaneous appendages (hair, hair and nails), both rich in keratin material, of which they feed.
The dermatophytes responsible for tinea cruris find the best situation for their development especially in the summer, when the combination of high and warm humidity favors sweating and the stagnation of sebaceous secretions in the inguino-crural zone.
As a rule, these fungi do not constitute any problem, as the skin barrier and the immune system exert a natural defense and control action with respect to their excessive proliferation. However, in the presence of some favorable conditions, these microorganisms behave as opportunists, ie they are able to "exploit" situations of immune weakness and overcome the resistance of the barriers of the human body, settling in the skin.
The species of fungi most commonly responsible for the onset of tinea cruris are:
- Trichophyton rubrum ;
- Trichophyton mentagrophytes;
- Epidermophyton floccosum .
Men are more affected by tinea cruris than women, due to the application of the scrotum to the thigh.
How the infection occurs
Tinea cruris is generally transmitted through the exchange of clothing, towels, sheets and objects for personal hygiene (such as razors and combs). In some cases, the infection can be contracted through sexual contact .
The most common initial source of infection is tinea pedis (or athlete's foot), with or without onychomycosis: in fact, it is possible that the disease results from the auto-inoculation of dermatophytes already present in another body area.
More rarely, contagion can occur through contact with animals (especially pets) or with the ground .
Predisposing factors
The main factors that can predispose to this infection are associated with the establishment of a hot-humid micro-environment in the inguino-crurale region and include:
- Habit to wear tight clothes (including swimwear) and synthetic clothes that hinder proper skin transpiration;
- Presence of concomitant dermatophytosis (especially la tinea pedis);
- Abundant sweating;
- Sport activity;
- Diabetes mellitus;
- Obesity responsible for the constant application of skin folds.
Excessive proliferation of fungi that cause tinea cruris may also be due to changes in skin pH and poor hygiene. Other predisposing factors include immunodeficiency states secondary to prolonged or frequent antibiotic therapies, use of cortisone drugs, chemotherapy, malnutrition, diabetes and other debilitating systemic diseases.
Who is most at risk
Tinea cruris is a fungal infection that is found most commonly in athletes and in obese people . In addition, those already suffering from another dermatophytosis, such as tinea pedis or ringworm of the body, are at greater risk of contracting this infection, especially when those affected do not resist the urge to scratch or touch existing lesions, favoring thus the dissemination of the fungus spores.
Signs and Symptoms
Tinea cruris typically begins with a rash extending from the crural fold above the adjacent inner portion of the thigh. From this site, the lesions can descend to semi-moon towards the upper part of the legs, but they can also ascend towards the pubis and the abdomen or extend towards the perianal region or the buttocks.
The rash of tinea cruris is made up of small erythematous and desquamative patches with an annular appearance, ie with a lighter central area and a clear and red margin. The appearance of these lesions is typically circular (also called "ringworm") and is also found in other forms of ringworm (such as tinea corporis): the eruption initially appears as a discoid macula that tends to widen in a centrifugal sense; as the inflammatory state undergoes spontaneous resolution, the center of the lesion returns to a lighter color (rosaceous), while the margin remains reddish.
The lesions of the tinea cruris are typically itchy, while the desquamating margins can be surmounted by vesicles . The rash associated with this fungal infection can be bilateral.
Tinea cruris can get complicated with maceration, miliaria, secondary bacterial infection or Candida intertrigo. Furthermore, adverse reactions to treatment, scratching dermatitis and lichenisation are possible. These conditions can cause persistent itching, pain and a burning sensation around the affected area.
Recurrences of tinea cruris are frequent, as fungi can repeatedly infect predisposed subjects. Exacerbations occur more often during the summer.
Diagnosis
The diagnosis of tinea cruris is formulated by the dermatologist on the basis of the anamnesis, clinical examination and microscopic observation of a sample of cutaneous scarifications.
Causative skin fungus can be identified by direct microscopic examination of fresh potassium hydroxide preparations (KOH) and positive laboratory cultures.
Differential diagnosis
Tinea cruris should be distinguished from:
- Contact dermatitis;
- Psoriasis;
- erythrasma;
- Chronic lichen simplex;
- Candidiasis.
In males, scrotum involvement is usually absent or mild. This clinical feature is important in distinguishing with Candida intertrigo, in which, on the contrary, scrotal skin is often inflamed. Furthermore, in candidiasis there are typical satellite lesions, while the eruption of tinea cruris is well localized.
Treatment
The treatment of tinea cruris depends on the severity of the clinical manifestations, but, usually, it involves the use of the most appropriate antifungal drugs, to be applied on the skin or to be taken orally, according to the indications of the dermatologist specialist.
In most cases, tinea cruris can be successfully treated with a topical antifungal (cream, lotion or gel), to be applied to the affected area once or twice a day for at least 7-10 days after the disappearance of the lesions. which generally occurs after about 2-3 weeks. Treatment options include: terbinafine, naftifina, miconazole, clotrimazole, ketoconazole, econazole and ciclopirox. During treatment, wear tight-fitting synthetic clothes should be avoided.
In patients with refractory, inflammatory or diffuse infections, the approach instead involves the intake of oral antifungals (such as itraconazole or terbinafine), once a day for about 3-6 weeks.
In the management of mycosis in the groin, the simultaneous treatment of tinea pedis (athlete's foot) and onychomycosis is also essential to reduce the risk of relapse.
With the appropriate diagnosis and therapy, the prognosis of tinea cruris is excellent; however, if the inguinal region is not kept dry and clean, recurrences are more likely.
Prevention and Useful Tips
Prevention of tinea cruris involves maintaining the clean and dry groin region. Infection is in fact favored by the onset of a hot-humid microenvironment at an inguino-crural level, due to the hindered evaporation of sweat, obesity or poor personal hygiene.
Useful measures to prevent tinea cruris include:
- Dry the groin area well after a hot bath, exercise or a particularly hot day;
- Wear cotton underwear and change it daily;
- Do not use tight-fitting clothing or clothes made with synthetic fibers;
- Avoid sharing towels, wipes, combs, limes or nail scissors with other people.
Finally, to combat the tendency to reinfection with tinea cruris, it is necessary to thoroughly disinfect all the objects used by the patient by boiling, dry cleaning, disinfectants and specific antifungal products.
