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

fungal infection Fungal infection, also known as mycosis, is 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 ti ...

of the

groin In human anatomy, the groin (the adjective is ''inguinal'', as in inguinal canal) is the junctional area (also known as the inguinal region) between the abdomen and the thigh on either side of the pubic bone. This is also known as the medial compa ...

and buttocks region, which occurs predominantly but not exclusively in men and in hot-humid climates. Typically, over the upper inner thighs, there is an intensely

itch Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

y red raised

rash A rash is a change of the human skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cr ...

with a scaly well-defined curved border. It is often associated with athletes foot 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 con ...

erythrasma Erythrasma is a superficial skin infection that causes brown, scaly skin patches. It is caused by '' Corynebacterium minutissimum'' bacteria, a normal part of skin flora (the microorganisms that are normally present on the skin). There are two ty ...

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, penis ...

and

seborrhoeic dermatitis Seborrhoeic dermatitis, sometimes inaccurately referred to as seborrhoea, is a long-term skin disorder. Symptoms include red, scaly, greasy, itchy, and inflamed skin. Areas of the skin rich in oil-producing glands are often affected including th ...

. 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

with a scaly well-defined border. There may be some blistering and weeping, and the rash can reach near to the

anus The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, de ...

. 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 h ...

, nodules and

pustules A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this s ...

) within the plaque. The plaque may reach the

scrotum The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum con ...

in men and the

labia majora The labia majora (singular: ''labium majus'') are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum. Together with the labia minora they form the labia of the vulva. The labia ...

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 sym ...

in women. The

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do no ...

is usually unaffected unless there is

immunodeficiency Immunodeficiency, also known as immunocompromisation, 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 a ...

or there has been use of

steroids A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and ...

. Affected people usually experience intense

itching Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

in the groin which can extend to the

Causes

Macroconidia of Epidermophyton floccosum (PHIL 4207 lores)

Tinea cruris is often associated with athletes foot 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 ''Epidermophyton floccosum'' is a filamentous fungus that causes skin and nail infections in humans. This anthropophilic dermatophyte can lead to diseases such as tinea pedis (athlete's foot), tinea cruris, tinea corporis and onychomycosis. Di ...

'' 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 humans, ...

'' and ''

Trichophyton verrucosum ''Trichophyton verrucosum'', commonly known as the cattle ringworm fungus, is a dermatophyte largely responsible for fungal skin disease in cattle, but is also a common cause of ringworm in donkeys, dogs, goat, sheep, and horses. It has a world ...

'' are involved. ''

Trichophyton interdigitale ''Trichophyton interdigitale'' is a clonal line within sexual species '' T. mentagrophytes''. It causes onychomycosis and tinea pedis in humans, and has never been isolated from animals. ''Trichophyton interdigitale'' isolates cannot be reliably ...

'' 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

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 athletes 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 unsaturated amine. Production and reactions All three allylamines, mono-, di-, and triallylamine, are produced by the treating allyl chlo ...

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. T ...

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 it ...

, econazole,

ketoconazole Ketoconazole, sold under the brand name Nizoral among others, is an antiandrogen and antifungal medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin infections such as tinea, cutaneous candi ...

, oxiconazole,

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), and ...

, 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, fungal nail infections, and ringworm including jock itch and athlete's foot. It is either taken by mouth or applied ...

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 by mou ...

can be given by mouth. The benefits of the use of topical steroids in addition to an antifungal is 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 are helpful.

Prognosis and complications

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 A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this sy ...

and secondary bacterial infection. Irritant and allergic contact dermatitis 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 ringworm, is a fungal infection of the skin. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the area affected. Symptoms begin four to fourteen days after exposure. Multiple ...

. It is uncommon in children.

References

External links

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