Jock Itch Information

Jock itch, also known as tinea cruris, is a fungal infection of the skin in the groin and upper thighs. The fungus that most commonly causes jock itch is called Trichophyton rubrum. Trichophyton rubrum also causes fungal infections of the toes and body. Lesions caused by jock itch can extend from the crease between the inner thigh and pelvis, over the adjacent upper inner thigh, and into the anal area.Jock itch differs from genital herpes in that it usually doesn’t develop on the scrotum or penis. It tends to spread in the inner thigh area instead. However, a jock itch rash may also affect the genitals and areas around the anus, rectum, or vagina. The skin may crack, scale and be painful, but it usually won’t present open lesions like it would with genital herpes. Genital herpes doesn’t cause long-term infections. Healthy skin returns after 3 weeks, although slight change in skin color may result.CausesThe fungus that most commonly causes jock itch is called Trichophyton rubrum. It also causes fungal infections of the toes and body. Under the microscope, this fungus looks like translucent, branching, rod-shaped filaments or hyphae. The width of the hyphae is uniform throughout which helps distinguish it from hair, which tapers at the end. Some hyphae appear to have bubbles within their walls, also distinguishing them from hair. Under most conditions these fungi inhabit only the dead skin cells of the epidermis.Jock itch is caused by the same fungus that causes ringworm (tinea cruris). Jock itch is much more common in men than in women and develops most frequently in warm weather. The infection begins in the skinfolds of the genital area and can spread to the buttocks, upper inner thighs, armpits and underneath the breasts. Usually the scrotum is not involved (unlike in yeast infection). Anyone can get jock itch. Jock itch named because it is usually athletes who get it, but it can affect anyone who tend to be overweight or sweat a lot.SymptomsThere are several different jock itch symptoms that will let you know if you have it. Do you notice a circular, raised, red rash around your groin? Have you been experiencing a lot of itching? Does it seem like the more you scratch, the more you itch? Have you had any flaking or peeling of your skin in the groin area? All of these are classic symptoms.A circular, red, raised rash with elevated edges. Itching and redness in your groin, including your genitals, inner thighs, buttocks and anal area. Flaking, peeling or cracking skin in your groin. Abnormally dark or light skin. You may have other fungal skin rashes such as athlete’s foot or ringworm on other body parts. TreatmentSevere infections, frequently recurring infections, or infections lasting longer than two weeks may require further treatment by your doctor. Stronger prescription medications, such as those containing ketoconazole or terbinafine, or oral antifungals may be needed. Antibiotics may be needed to treat bacterial infections that occur in addition to the fungus (for example, from scratching the area).Side effects from oral medications include gastrointestinal upset, rash and abnormal liver function. Taking other medications, such as antacid therapies for ulcer disease or gastroesophageal reflux disease (GERD), may interfere with the absorption of these drugs. Oral medications for fungal infection may alter the effectiveness of warfarin, an anticoagulant drug that decreases the clotting ability of your blood.

Clinical Presentation-Skin Disorders

Tinea capitis, or “ringworm” of the scalp, presents as one or more sharply marginated plaques of partial alopecia. Inflammation and scale are present, but often these two changes are quite minimal. The recognition of broken hairs (stubble and black dots at the follicular orifices) is the best clue to correct diagnosis. Nearly all cases occur in children, but the diagnosis should be considered in any adult presenting with evidence of localized alopecia . Kerion formation is a complication that occurs in about 10% of cases. This represents a sensitization phenomenon whereby the fungi induce a remarkably brisk inflammatory reaction with resulting pustulation, crusting, and edema formation. Wood’s lamp examination does not reveal fluorescence in the most common forms of tinea capitis or in kerion formation. Unfortunately, KOH preparations are difficult for the inexperienced to interpret. For this reason, any suspected diagnosis requires the plucking of infected hairs for fungal culture. Course and PrognosisTinea capitis and zoophilic tinea corporis usually resolve spontaneously after 6 to 12 months of activity. Tinea pedis, tinea cruris, and anthropophilic tinea corporis continue indefinitely. There are, however, periods of relative quiescence and exacerbation. All of these fungal diseases respond well to treatment, but with the exception of tinea capitis and zoophilic tinea corporis infections, recurrence following treatment is rather likely. PathogenesisTinea pedis, tinea cruris, and anthropophilic tinea corporis are most commonly caused by Trichophyton rulnum. Trichophyton interdigitate and Epidermophhyton floccoswn infections are also seen. Generally, one cannot predict the causative organism on the basis of clinical appearance. Zoophilic tinea corporis can be caused by Microsporum canis, Trichophyton mentagrophytes, and Trichophyton verrucosum. Tinea capitis is caused by Trichophyton tonsurans in 90% of cases. The likelihood of inoculation with any of these fungi is enhanced if cuts and scratches are present on the skin. Clinical evidence of infection following inoculation is enhanced by the presence of warmth and moisture, such as occurs in the groin and under footwear. Depression of cell-mediated immune responsiveness, as in atopic patients, is a major predisposing factor for the development of T. rubrum infection. TherapyTinea cruris and those cases of tinea pedis that involve only the web spaces can be treated with any of the topical antifungal agents. Other forms of tinea pedis usually require the use of griseofulvin. Mild cases of tinea corporis also respond well to topical agents. Extensive disease and those cases with a component of follicular involvement are best treated with griseofulvin. Tinea capitis requires the use of griseofulvin. Orally administered ketoconazole therapy is rarely appropriate for either tinea corporis or capitis. Kerion on nation, if present, can be treated with intralesional steroid injections or with a short burst of systemically administered steroids.

Tinea capitis, or “ringworm” of the scalp, presents as one or more sharply marginated plaques of partial alopecia. Inflammation and scale are present, but often these two changes are quite minimal. The recognition of broken hairs (stubble and black dots at the follicular orifices) is the best clue to correct diagnosis. Nearly all cases occur in children, but the diagnosis should be considered in any adult presenting with evidence of localized alopecia . Kerion formation is a complication that occurs in about 10% of cases. This represents a sensitization phenomenon whereby the fungi induce a remarkably brisk inflammatory reaction with resulting pustulation, crusting, and edema formation. Wood’s lamp examination does not reveal fluorescence in the most common forms of tinea capitis or in kerion formation. Unfortunately, KOH preparations are difficult for the inexperienced to interpret. For this reason, any suspected diagnosis requires the plucking of infected hairs for fungal culture.
Course and Prognosis

Tinea capitis and zoophilic tinea corporis usually resolve spontaneously after 6 to 12 months of activity. Tinea pedis, tinea cruris, and anthropophilic tinea corporis continue indefinitely. There are, however, periods of relative quiescence and exacerbation. All of these fungal diseases respond well to treatment, but with the exception of tinea capitis and zoophilic tinea corporis infections, recurrence following treatment is rather likely.
Pathogenesis

Tinea pedis, tinea cruris, and anthropophilic tinea corporis are most commonly caused by Trichophyton rulnum. Trichophyton interdigitate and Epidermophhyton floccoswn infections are also seen. Generally, one cannot predict the causative organism on the basis of clinical appearance. Zoophilic tinea corporis can be caused by Microsporum canis, Trichophyton mentagrophytes, and Trichophyton verrucosum. Tinea capitis is caused by Trichophyton tonsurans in 90% of cases.

The likelihood of inoculation with any of these fungi is enhanced if cuts and scratches are present on the skin. Clinical evidence of infection following inoculation is enhanced by the presence of warmth and moisture, such as occurs in the groin and under footwear. Depression of cell-mediated immune responsiveness, as in atopic patients, is a major predisposing factor for the development of T. rubrum infection.
Therapy

Tinea cruris and those cases of tinea pedis that involve only the web spaces can be treated with any of the topical antifungal agents. Other forms of tinea pedis usually require the use of griseofulvin. Mild cases of tinea corporis also respond well to topical agents. Extensive disease and those cases with a component of follicular involvement are best treated with griseofulvin. Tinea capitis requires the use of griseofulvin. Orally administered ketoconazole therapy is rarely appropriate for either tinea corporis or capitis. Kerion on nation, if present, can be treated with intralesional steroid injections or with a short burst of systemically administered steroids.

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