| Tinea cruris | |
|---|---|
| Other names | Eczema marginatum, crotch itch, crotch rot, dhobi itch, gym itch, jock itch, jock rot, scrot rot[1][2]: 303 |
 | |
| Tinea cruris on the groin of a man | |
| Specialty | Dermatology |
| Symptoms | Itch, rash in groin |
| Risk factors |
|
| Diagnostic method | Microscopy and culture of skin scrapings |
| Differential diagnosis | |
| Prevention |
|
| Medication | Topicalantifungal medications |
Tinea cruris (TC), also known asjock itch, is a common type of contagious, superficialfungal infection of thegroin andbuttocks region, which occurs predominantly but not exclusively in men and in hot-humid climates.[3][4]
Typically, over the upper inner thighs, there is an intensely itchy red raised rash with ascaly well-defined curved border.[3][4] It is often associated withathlete's foot andfungal nail infections, excessive sweating, and sharing of infected towels or sports clothing.[4][5][6] It is uncommon in children.[4]
Its appearance may be similar to some other rashes that occur in skin folds includingcandidal intertrigo,erythrasma,inverse psoriasis andseborrhoeic dermatitis. Tests may include microscopy and culture of skin scrapings.[7]
Treatment is with topicalantifungal medications and is particularly effective if symptoms have recent onset.[5][6] Prevention of recurrences include treating concurrent fungal infections and taking measures to avoid moisture build-up including keeping the groin region dry, avoiding tight clothing and losing weight if obese.[8]
Other names include "jock rot or crotch rot",[9] "dhobi itch",[10] "crotch itch",[11] "scrot rot",[12] "gym itch", "ringworm of groin" and "eczema marginatum".[13]
Typically, over the upper inner thighs, there is a red raised rash with ascaly well-defined border. There may be some blistering and weeping, and the rash can reach near to theanus.[3] The distribution is usually on both sides of the groin and the center may be lighter in colour.[8] The rash may appear reddish, tan, or brown, with flaking, rippling, peeling, iridescence, or cracking skin.[14]
If the person is hairy, hair follicles can become inflamed resulting in some bumps (papules,nodules andpustules) within the plaque. The plaque may reach thescrotum in men and thelabia majora andmons pubis in women. Thepenis is usually unaffected unless there isimmunodeficiency or there has been use ofsteroids.[4]
Affected people usually experience intense itching in the groin which can extend to theanus.[3][4]
.jpg)
Tinea cruris is often associated withathlete's foot andfungal nail infections.[4][5] Rubbing from clothing, excessive sweating, diabetes and obesity are risk factors.[6][8] It is contagious and can be transmitted person-to-person by skin-to-skin contact or by contact with contaminated sports clothing and sharing towels.[3][5]
The type of fungus involved may vary in different parts of the world; for example,Trichophyton rubrum andEpidermophyton floccosum are common in New Zealand.[7] Less commonlyTrichophyton mentagrophytes andTrichophyton verrucosum are involved.[8]Trichophyton interdigitale has also been implicated.[5]
Tests are usually not needed to make a diagnosis, but if required, may include microscopy and culture of skin scrapings, aKOH examination to check for fungus, or skin biopsy.[3][7]
The symptoms of tinea cruris may be similar to other causes of itch in the groin.[3] Its appearance may be similar to some other rashes that occur in skin folds includingcandidal intertrigo,erythrasma,inverse psoriasis andseborrhoeic dermatitis.[7]
To prevent recurrences of tinea cruris, concurrent fungal infections such as athlete's foot need to be treated. Also advised are measures to avoid moisture build-up including keeping the groin region dry, avoiding tight clothing, and losing weight if obese.[8] People with athlete's foot or tinea cruris can prevent spread by not lending their towels to others.[5]
Tinea cruris is treated by applyingantifungal medications of theallylamine orazole type to the groin region. Studies suggest thatallylamines (naftifine andterbinafine) are a quicker but more expensive form of treatment compared to azoles (clotrimazole,econazole,ketoconazole,oxiconazole,sulconazole).[6] If the symptoms have been present for long or the condition worsens despite applying creams, terbinafine oritraconazole can be given by mouth.[5]
The benefits of the use oftopical steroids in addition to an antifungal are unclear.[15] There might be a greater cure rate but no guidelines currently recommend its addition.[15] The effect ofWhitfield's ointment is also unclear,[15] but when given, it is prescribed at half strength.[5]
Wearing cotton underwear and socks, in addition to keeping the groin dry and using antifungal powders, is helpful.[16]
Tinea cruris is not life-threatening and treatment is effective, particularly if the symptoms have not been present for long.[5] However, recurrence may occur. The intense itch may lead tolichenification and secondary bacterial infection. Irritant and allergiccontact dermatitis may be caused by applied medications.[8]
Tinea cruris is common in hot-humid climates, and is the second most common clinical presentation fordermatophytosis.[8] It is uncommon in children.[4]