Tinea cruris (TC), also known as jock itch, is a common type of contagious, superficial

fungal infection Fungal infection, also known as mycosis, is a disease caused by fungi. Different types are traditionally divided according to the part of the body affected: superficial, subcutaneous, and systemic. Superficial fungal infections include common ...

of the

groin In human anatomy, the groin, also known as the inguinal region or iliac region, is the junctional area between the torso and the thigh. The groin is at the front of the body on either side of the pubic tubercle, where the lower part of the abdom ...

and

buttocks The buttocks (: buttock) are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region. In humans, the buttocks are located between the lower back and the perineum. They are composed of a lay ...

region, which occurs predominantly but not exclusively in men and in hot-humid climates. Typically, over the upper inner thighs, there is an intensely itchy red raised rash with a scaly well-defined curved border. It is often associated with

athlete's foot Athlete's foot, known medically as ''tinea pedis'', is a common skin infection of the feet caused by a fungus. Signs and symptoms often include itching, scaling, cracking and redness. In rare cases the skin may blister. Athlete's foot fungus ...

and fungal nail infections, excessive sweating, and sharing of infected towels or sports clothing. It is uncommon in children. Its appearance may be similar to some other rashes that occur in skin folds including

candidal intertrigo Candidal intertrigo is an infection of the skin by '' Candida albicans'', more specifically located between intertriginous folds of adjacent skin. See also * Candidiasis * Intertrigo * Skin lesion A skin condition, also known as cutaneous c ...

, erythrasma,

inverse psoriasis Inverse psoriasis or flexural psoriasis is a form of psoriasis that selectively, and often exclusively, involves the folds, recesses, and flexor surfaces such as the ears, axillae, groin folds, inframammary folds, navel, intergluteal cleft, peni ...

and

seborrhoeic dermatitis Seborrhoeic dermatitis (also spelled seborrheic dermatitis in American English) is a long-term skin disorder. Symptoms include flaky, scaly, greasy, and occasionally itchy and inflamed skin. Areas of the skin rich in oil-producing glands are ...

. Tests may include microscopy and culture of skin scrapings. Treatment is with topical

antifungal medication An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as cry ...

s and is particularly effective if symptoms have recent onset. 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.

Names

Other names include "jock rot", "dhobi itch", "crotch itch", "scrot rot", "gym itch", "ringworm of groin" and "eczema marginatum".

Signs and symptoms

Typically, over the upper inner thighs, there is a red raised rash with a scaly well-defined border. There may be some blistering and weeping, and the rash can reach near to the

anus In mammals, invertebrates and most fish, the anus (: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the ''exit'' end of the digestive tract (bowel), i.e. the opposite end from the mouth. Its function is to facil ...

. The distribution is usually on both sides of the groin and the center may be lighter in colour. The rash may appear reddish, tan, or brown, with flaking, rippling, peeling, iridescence, or cracking skin. If the person is hairy, hair follicles can become inflamed resulting in some bumps (

papules A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some ...

, nodules and pustules) within the plaque. The plaque may reach the

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

in men and the

labia majora In primates, and specifically in humans, the labia majora (: labium majus), also known as the outer lips or outer labia, are two prominent Anatomical terms of location, longitudinal skin folds that extend downward and backward from the mons pubis ...

and

mons pubis In human anatomy, and in mammals in general, the ''mons pubis'' or pubic mound (also known simply as the mons , and known specifically in females as the ''mons Venus'' or ''mons veneris'') is a rounded mass of fatty tissue found over the pubic s ...

in women. The

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

is usually unaffected unless there is

immunodeficiency Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that aff ...

or there has been use of

steroids A steroid is an organic compound with four fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter mem ...

. Affected people usually experience intense itching in the groin which can extend to the

Causes

Tinea cruris is often associated with

and fungal nail infections. Rubbing from clothing, excessive sweating, diabetes and obesity are risk factors. 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. The type of fungus involved may vary in different parts of the world; for example, ''

Trichophyton rubrum ''Trichophyton rubrum'' is a dermatophytic fungus in the phylum Ascomycota. It is an exclusively clonal, anthropophilic saprotroph that colonizes the upper layers of dead skin, and is the most common cause of athlete's foot, fungal infection of ...

'' and '' Epidermophyton floccosum'' are common in New Zealand. Less commonly ''

Trichophyton mentagrophytes ''Trichophyton mentagrophytes'' is a species in the fungal genus '' Trichophyton''. It is one of three common fungi which cause ringworm in companion animals. It is also the second-most commonly isolated fungus causing tinea infections in human ...

'' and '' Trichophyton verrucosum'' are involved. '' Trichophyton interdigitale'' has also been implicated.

Diagnosis

Tests are usually not needed to make a diagnosis, but if required, may include microscopy and culture of skin scrapings, a KOH examination to check for fungus, or skin biopsy.

Differential diagnosis

The symptoms of tinea cruris may be similar to other causes of itch in the groin. Its appearance may be similar to some other rashes that occur in skin folds including

, erythrasma,

and

Prevention

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. People with athlete's foot or tinea cruris can prevent spread by not lending their towels to others.

Treatment

Tinea cruris is treated by applying

s of the

allylamine Allylamine is an organic compound with the formula C3H5NH2. This colorless liquid is the simplest stable Alkene, unsaturated amine. Production and reactions All three allylamines, mono-, di-, and triallylamine, are produced by the treating allyl ...

azole Azoles are a class of five-membered heterocyclic compounds containing a nitrogen atom and at least one other non-carbon atom (i.e. nitrogen, sulfur, or oxygen) as part of the ring. Their names originate from the Hantzsch–Widman nomenclature. Th ...

type to the groin region. Studies suggest that allylamines (naftifine and terbinafine) are a quicker but more expensive form of treatment compared to azoles (

clotrimazole Clotrimazole, sold under the brand name Lotrimin, among others, is an antifungal medication. It is used to treat vaginal yeast infections, oral thrush, diaper rash, tinea versicolor, and types of ringworm including athlete's foot and jock itc ...

, econazole,

ketoconazole Ketoconazole, sold under the brand name Nizoral, among others, is an antiandrogen, antifungal drug, antifungal, and antiglucocorticoid medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin inf ...

oxiconazole Oxiconazole (trade names Oxistat in the US, Oxizole in Canada) is an antifungal medication typically administered in a cream or lotion to treat skin infections, such as athlete's foot, jock itch and ringworm. It can also be prescribed to treat th ...

miconazole Miconazole, sold under the brand name Monistat among others, is an antifungal medication used to treat ring worm, pityriasis versicolor, and yeast infections of the skin or vagina. It is used for ring worm of the body, groin (jock itch), a ...

, sulconazole). If the symptoms have been present for long or the condition worsens despite applying creams,

terbinafine Terbinafine, sold under the brand name Lamisil among others, is an antifungal medication used to treat pityriasis versicolor, onychomycosis, fungal nail infections, and ringworm including jock itch and athlete's foot. It is either oral adminis ...

itraconazole Itraconazole, sometimes abbreviated ITZ, is an antifungal medication used to treat a number of fungal infections. This includes aspergillosis, blastomycosis, coccidioidomycosis, histoplasmosis, and paracoccidioidomycosis. It may be given ...

can be given by mouth. The benefits of the use of topical steroids in addition to an antifungal are unclear. There might be a greater cure rate but no guidelines currently recommend its addition. The effect of Whitfield's ointment is also unclear, but when given, it is prescribed at half strength. Wearing cotton underwear and socks, in addition to keeping the groin dry and using antifungal powders, is helpful.

Prognosis

Tinea cruris is not life-threatening and treatment is effective, particularly if the symptoms have not been present for long. However, recurrence may occur. The intense itch may lead to lichenification and secondary bacterial infection. Irritant and allergic

contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes ...

may be caused by applied medications.

Epidemiology

Tinea cruris is common in hot-humid climates, and is the second most common clinical presentation for

dermatophytosis Dermatophytosis, also known as tinea and ringworm, is a fungal infection of the skin (a dermatomycosis), that may affect skin, hair, and nails. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the area aff ...

. It is uncommon in children.

References

External links

eMedicineHealth.com
{{Mycoses Animal fungal diseases Mycosis-related cutaneous conditions