This Week's Topic:
Summer remains in full swing in the SE United States, and in many other parts of the world as well. And, with the summer heat and humidity comes a much greater likelihood that one will develop either tinea cruris, tinea pedis, or both. . .especially if one is an adult male. These very sophisticated sounding medical illnesses translate easily into the nagging discomforts of "jock itch" and "athlete's foot" respectively. Why do summer heat and humidity increase the likelihood of these plagues? As many of us are spending more time by pools, in wet bathing suits or sweaty gym clothes, and tromping around in moist clothing, we're setting ourselves up for these very common fungal infections of the skin. Okay. . . just scratching the surface now. If you're itching to know more about who gets tinea, how we get it, how to treat it, and most importantly, how to prevent these pesky infections, read on.
Superficial fungal infections are among the most common skin diseases--affecting millions of people worldwide. Tinea infections all belong to a class of fungi known as Dermatophytes. Dermatophytes preferentially invade the dead keratin of skin, hair, and nails. However, their itchy assault on our bodies is limited strictly to the outer layers of our epidermis (the most superficial portion of our skin). In addition to tinea pedis and tinea cruris, there are other common forms of tinea infections, which are closely related and likewise classified by their anatomic locations. For example, tinea capitis affects the scalp, tinea corporis is the typical "ringworm" of the body, tinea barbae affects the bearded area and neck, and tinea unguium is the fungus that invades toenails and causes those misshapen, yellowed claws that make such a statement when one is barefoot or in sandals. Pruritis, or itching, is the main symptom of most forms of tinea. In tinea pedis, the infection occurs most often in the toe webs and on the sole of the foot; often only one foot is affected. Predisposing factors for increased risk include: moist conditions, communal baths, atopy (an inherited tendency for easily inflamed skin--often in people with other allergies such as asthma and hay fever), immunocompromised states (such as AIDS, cancer, patients on chemotherapy or longterm steroids), and there even seems to be a genetic predisposition as well! But, overwhelmingly, the infections occur most commonly in good ole healthy sweaty folks. I'm restricting this week's discussion to athlete's foot and jock itch because they're usually the most 'intimate' of the bunch. . .and the hardest to 'get to' in polite company when the prickling and burning set in.
Tinea cruris occurs almost exclusively in adult men. The reason for this preferential targeting is the adult male anatomy, which allows moisture to accumulate with greater ease in the skin folds of the groin. Women CAN get the infection, but it's much less common--tending to prefer the full-figured types who have large overlapping, moist skin folds in their groin (isn't THAT a pretty picture?) Itching is common, and there is inflammation with well-defined margins that extend from groin to the inner thighs. There can be scaling and blisters associated with the rash, and unlike yeast (candida) infections, it does not affect the penis, scrotum or vagina. Dermatophytes all thrive in warm, moist areas. Guys, can you think of a single, outdoor activity during the summer months in the Southeastern United States that doesn't create this conducive breeding ground on the soles of your feet and/or in your groin area? We're a set-up without appropriate precautions! Unless you're a professional baseball player, it's generally not socially acceptable to scratch your crotch in a public setting. However, with tinea cruris, there's a great temptation!
Athlete's Foot is the most common dermatophyte infection. Tinea pedis attacks the toe webs and the soles of the feet preferentially. It commonly involves only one foot, and once, again, is most common in men--especially those in the 20 to 40 year old age range. Moist, abraded skin on the feet (especially between the toes) greatly increases one's chance of infection. The rash is itchy and creates inflammation, fissuring, and scaling. Both tinea pedis and tinea cruris can lead to secondary bacterial infections because of the open, irritated skin lesions. And, interestingly, tinea pedis is often the source of a man's subsequent tinea cruris infection. . .transferring the fungus from feet to crotch by scratching.
The definitive diagnosis of tinea infections can be made by looking at skin/nail scraping under a microscope. . .though generally healthy people with the classic presentations respond to empiric therapy without the need for this testing. However, allergic dermatitis, psoriasis, impetigo, yeast infections, and other bacterial infections can occasionally mimic dermatophytic infections, and should be considered in the more recalcitrant and/or severe cases.
In most cases, jock itch and athlete's foot can be treated at home with over-the-counter creams, ointments, and powders available in most pharmacies. But, check the directions on the preparations. . .since not all preparations for athlete's foot are appropriate for use in the more sensitive groin area. I've seen a few male patients dancing the tinea trot after they had incorrectly assumed that what's good for the feet should work on more delicate body parts as well! And, by all means, use the preparations LONG enough. The most common mistake I see,is people stopping the use of the preparations too soon. A minimum of TWO weeks is needed in all cases. . .sometimes up to 6 weeks for complete cure. Tinea may 'retreat' to a subcutaneous 'foxhole' early on. . .only to reemerge with a vengeance if one is not diligent in the continued use of topical treatments for the recommended time period.
Prevention is the key for both of these intimate itches. Since both athlete's foot and jock itch need warm, most, dark environments to flourish. . .keeping feet and groin areas clean and dry is always the first step. Bathe or shower regularly. . .and rinse completely. And, folks, DO wash the bottoms of your feet. . .with SOAP and water! I am amazed at the number of folks who have never thought it necessary to wash their feet at all--especially the bottoms of them. Avoid strong and/or deodorant soaps as they can be irritating. . .esp. in the groin area. Dry thoroughly after bathing. Change underwear at least once a day, more often if you work out or sweat heavily. . .and loose fitting, cotton boxers are better than tightly fitting underwear if you're prone to tinea cruris. Talcum powder or plain cornstarch sprinkled on feet and/or dusted in groin area can help absorb moisture between baths. And, you athletes. . .wash athletic supporters, gym shorts, and socks between each use. . .and avoid storing damp clothes in gym bags or lockers. Don't share towels, and use a fresh one each time you shower. . .again don't store used ones in your gym bag or locker for reuse without washing. Get out of wet swim suits or sweaty clothing as soon as possible. And, sleeping naked allows the groin area to remain dry better than wearing pajamas or underwear to bed. (YES, you heard IT from a doctor) If you are the unfortunate victim of both tinea cruris and tinea pedis simultaneously. . .make sure to put your socks on BEFORE your underwear. That way, your underwear won't be contaminated by your athlete's foot infection on it's way up stream.
If topical over the counter preparations DON'T work, there are prescription topical preparations and even pills/capsules for the more recalcitrant tinea infections. . .especially one's involving toenails and fingernails. But, the latter can have serious interactions with other medications, and will need careful monitoring by your doctor.
If you remember the rules of careful summer hygiene, you'll most likely avoid these pesky, pruritic plagues. Put your best foot forward. . .and let these dastardly dermatophytes take no cheap crotch shots at you! Tinea turmoil doesn't have to be part of your summer routine if you practice appropriate preventive measures.
Stephen L. Hines, M.D.
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