A 16-year-old male came to clinic because of a groin rash that had been present for a week. It was only slightly bothersome because of the location and was slightly pruritic. He had tried some powder and also lotion but this did not help. The rash was now spreading circumferentially. He was a multi-sport athlete. The past medical history was positive for tinea pedis a few weeks previously that he had used anti-fungal cream for with resolution. He also had a history of tinea pedis more than 1 year ago. The family history was positive for a younger sister who was being treated for ringworm.
The review of systems was negative.
The pertinent physical exam showed a healthy appearing male with normal vital signs and growth parameters. His skin examination showed a 7 cm round-oval lesion in the left inguinal fold with lighter coloring in the center and a raised edge. It was difficult to tell if there was scale as he had just showered. There was a 3 cm lesion above the gluteal cleft that appeared similarly but had some scale present. All other areas of the skin appeared uninfected including his feet.
The diagnosis of tinea cruris was made. The pediatrician recommended over-the-counter antifungal cream to be used twice a day for at least 14 days. “Sounds like you are re-infecting yourself or you are getting infected from your sibling or all the sports you do.
I have some ideas about how you can prevent this from occurring again,” she said.
Superficial fungal infections are very common. “Dermatophytes are molds that can invade the stratum corneum of the skin or other keratinized tissues derived from the epidermis, such as hair and nails. Organisms most commonly affect the scalp, feet, groin and nails.”
Dermatophytes can be anthropophilic (human to human transmission), zoophilic (animal to human transmission) or geophilic (fomite to human transmission). Zoophilic dermatophytes are usually uncommon sources of human infection. Microsporum canis is the most common zoophilic dermatophyte and it can infect humans with close contact but this is less common than anthropophilic organisms. A common example of a geophilic dermatophyte is Microsporum gypseum and again it is not very commonly spread. Human to human or self-inoculation is the most common way tinea infections are spread. Anthropophilic organisms commonly encountered include Trichophyton rubrum, Triphophyton mentagrophytes, Trichophyton tonsurans, and Epidermophyton floccosum.
A review of common tinea infections and presentations can be found here
Tinea tends to affect the glabrous skin or skin without prominent hair. The primary method of transmission between people is contact with infected desquamated skin scales and also infected hair. Molds tend to grow in warm humid environments, so it is not surprising that areas of the bodies with these characteristics are commonly affected. Similarly, environmental exposure such as public shower rooms where large numbers of people congregate may also increase the risk of acquiring or spreading some tinea infections especially tinea pedis. Other areas where infected scale or hair could be contacted would be shared combs, brushes, hats or other clothing.
Prevention of tinea includes not sharing personal items such as combs, brushes, worn and unwashed clothing, towels or bedding. Additionally, frequent clothes changes and washing of potentially infected clothing and towels/bedding should decrease the amount of potential infected material on the clothing, etc. thereby decreasing transmission. Affected body areas should be covered when around others or in venues where people could become infected (e.g. sports practices and competitions, etc.). However, increasing the airflow by wearing loose-fitting garments can decrease the humidity and temperature thereby potentially decreasing dermatophyte growth. Wearing shower shoes in communal bathing facilities is a good practice.
Some authors note that there is an increased risk of tinea cruris after an episodes of tinea pedis. They suspect that during clothing changes and/or grooming, the affected foot or feet is placed near the genital area in a semi-crossed legged position thereby increasing transmission risk. They recommend covering the feet with socks prior to dressing other areas of the body.
Treatment of tinea infections includes antifungal medication and mechanical debridement if appropriate such as nail hygiene.
Questions for Further Discussion
1. How do you treat fungal nail infections? A review can be found here
2. Why do you treat some fungal infections with topical medication and others with oral medication?
- Symptom/Presentation: Infections
- Age: Teenager
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
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Gupta AK, Chaudhry M, Elewski B. Tinea corporis, tinea cruris, tinea nigra, and piedra. Dermatol Clin. 2003 Jul;21(3):395-400, v.
Panackal AA, Halpern EF, Watson AJ. Cutaneous fungal infections in the United States: Analysis of the National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS), 1995-2004. Int J Dermatol. 2009 Jul;48(7):704-12.
Bhadauria S, Kumar P. Broad spectrum antidermatophytic drug for the control of tinea infection in human beings. Mycoses. 2012 Jul;55(4):339-43.
Alter SJ, McDonald MB, Schloemer J, Simon R, Trevino J. Common Child and Adolescent Cutaneous Infestations and Fungal Infections. Curr Probl Pediatr Adolesc Health Care. 2018 Jan;48(1):3-25.
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa