Superficial fungal infections of the skin, known as dermatophytes, are some of the most common self-treatable trivial medical conditions. As opposed to more serious fungal conditions, such as candidiasis or sporotrichosis, dermatophytes are limited to the upper layer of skin, where they subsist on the keratinized dead skin cells; in most cases, they are easy to eradicate. Tinea cruris (jock itch) is one of these bothersome dermatophytes that is completely curable with nonprescription products, making it a prime target for judicious pharmacist counseling.
As many as one in five Americans has a dermatophyte infection at any particular time. The overall prevalence is exceeded only by acne, regarding the number of people affected. In the United States, the most common dermatophytic infection is athlete's foot (tinea pedis). Tinea corporis and tinea cruris are also quite common. The exact incidence of tinea cruris is difficult to determine. It is not a reportable disease, and patients are able to recognize it and treat it until it is cured. In one study, investigators in São Paulo, Brazil, discovered that 13.9% of dermatophytoses were tinea cruris.
When the pharmacist counsels a patient complaining of manifestations that possibly indicate tinea cruris, it is helpful to understand the epidemiology. It is less common in some groups, making other conditions more likely. There are few recent data from the U.S. regarding its incidence. However, some clues can be drawn from Brazilian studies.
Traditionally, tinea cruris has not been considered common in prepubertal children; however, a study of 137 Brazilian children younger than 12 found 10 cases of tinea cruris. Nonetheless, it is more common in older patients, even the elderly. In a Brazilian study, the primary ages were 16 to 30 for males and 26 to 40 for females.
There is widespread agreement that males are the most common victims of tinea cruris infection.[1,5,7,8,9,10] This has been confirmed by studies in Brazil (with a 4:1 ratio of males:females affected).
The value of epidemiological factors in tinea cruris is to demonstrate those groups who are most prone to develop a condition. However, in the case of tinea cruris, such epidemiological factors as age and gender tell only part of the story. Other factors predispose the older male patient to tinea cruris.
Clothing that fits tightly is thought to be a predisposing factor in tinea cruris.[1,8] For women, wearing pants as opposed to dresses is also indicated as a predisposing factor. Two aspects are relevant here. The first involves the potential of moisture build-up beneath tight clothing. Another is the risk to the patient from wearing clothing that has become contaminated and is not cleaned well. This latter point leads to the specific recommendation that patients boil the underclothing thoroughly to minimize the possibility of reinfection.
Some authors also stress that humidity and moisture are contributory.[9,10] The suspected underlying cause is similar to the growth patterns observed in molds, mildew, and similar plant species. Specifically, they favor warmth and moisture. Thus, the role of tight, occlusive clothing becomes more apparent. Furthermore, one can project that climates where humidity is high and temperatures are higher would exhibit increased rates of tinea cruris. Wearing occlusive, wet clothing would also create the ideal conditions for fungal growth. This finding also explains the preference for male patients. Male genitalia have more skinfolds. In addition, female clothing (e.g., skirts, dresses) typically allows evaporation more readily than a tight pair of men's pants.
Following the aforementioned line of thought regarding causation, it would seem axiomatic that obesity would predispose the patient to tinea cruris. Skinfolds that overlap other skin inhibit evaporation of moisture, creating the moist and warm conditions needed for tinea cruris proliferation.[5,12]
Patients with tinea cruris may ask the pharmacist how they acquired the infection. First, it is helpful to identify the organisms responsible, including Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum.[14,15] All these organisms also cause tinea pedis, a clue to the possible sources for a cruris infection.[1,2,5,16]
The potential chain of causation could be as follows. A patient develops a case of athlete's foot. Following the morning shower, the patient uses a single towel to dry the entire body. If the feet are dried before the groin, fungal organisms remaining on the towel are transferred to the groin area, where the moisture and warmth allow them to grow. This process is known as autoinoculation and conceivably could also occur when the patient has infected toenails (onychomycosis). However, the condition could also appear de novo in a patient who does not have concomitant athlete's foot. In this case, a person may use an inadequately cleaned towel contaminated by contact with another individual.
Tinea cruris is not often considered to be a sexually transmitted disease, but skin-to-skin genital contact could lead to inoculation in the partner's groin. While the condition is not as common in females, it can occur due to sexual transfer, and simultaneous treatment for the male partner should also be recommended to prevent reinoculation.
Tinea cruris exists primarily near the areas of the groin and surrounding skin that are moist for a large part of the day as a result either of being occluded by clothing or of being covered by skinfolds (known as intertriginous skin). Thus, its dominant targets are the upper, inner thigh, inguinal folds, perineal area, and buttocks.[5,7,8] The penis and scrotum are less likely to be affected, but it may extend upward to the lower abdominal area, adjacent to the genitalia.[7,10] The typical lesion is a pruritic-ringed plaque, which is usually erythematous, scaling, and with clearly outlined margins. Small papules or pustules may be at the outer margins of the plaque, and the plaque is usually bilateral.[1,2]
Nonprescription treatment is relatively simple and provides a complete cure when products are used as directed. However, the products are not to be used on any tinea of the scalp or nails, and they are not to be used to treat vaginal yeast infections. They are also not indicated for diaper rash. Products for this condition must not be used near the mouth or eyes. Patients should wash their hands after application to prevent autoinoculation and/or transfer to others. Patients should discontinue use and see a physician if irritation occurs or if the infection remains after the recommended maximal treatment time.
Butenafine hydrochloride 1% is found in Lotrimin Ultra Cream. It is not recommended in patients younger than 12. Patients apply the product once daily for two weeks.
Clotrimazole 1% is the active ingredient in Lotrimin AF Cream and Solution. It is applied twice a day in those 2 years and older for two weeks, or as directed by a physician.
Miconazole nitrate 2% is found in Cruex Prescription Strength Spray Powder, Desenex Spray Powder and dusting powder, Lotrimin AF Spray Powder, and Micatin Antifungal Liquid Spray and Antifungal Spray Powder. The medication is applied twice daily in patients ages 2 years and older for two weeks.
Terbinafine hydrochloride 1% is found in such products as Lamisil AT Spray Pump, Solution Dropper and Cream, and Desenex Max Cream. The products are not recommended for patients younger than 12 years. The patient should apply or spray the infected area once daily (morning or night) for one week, or as directed by a physician. At this time, these products claim to involve the shortest treatment time to cure tinea cruris.[19,20,21]
Tolnaftate 1% is found in such products as Tinactin Antifungal Spray Powder and Aftate Antifungal Liquid Spray. Tolnaftate is safe and effective in curing tinea cruris in patients ages 2 years and older when used twice daily for two weeks.
Some products contain ingredients of unknown safety and/or efficacy. One is Blue Star Ointment, which contains camphor in an unlabeled concentration in a vehicle of unknown composition. The efficacy and safety of camphor in any fungal condition is not known. It could also produce discomfort or overt pain if the patient has wounded or broken skin, as in the papules and pustules that may occur with tinea cruris. Camphor should be avoided in all fungal conditions.
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US Pharmacist. 2005;30(9) © 2005 Jobson Publishing
Cite this: Tinea Cruris in Men: Bothersome But Treatable - Medscape - Aug 17, 2005.