While working as an automotive technician in Palm Springs, one August we had an unusual series of tropical storms originating in Baja, Mexico. Every day the weather forecast called for highs in the 115F – 118F range with a 90% chance of afternoon thundershowers. This went on for 3 or 4 weeks. As you can imagine, working in an open air service bay was not fun. After a couple of days I developed a painful rash in the area of my thighs and groin. Washing at night and using talcum powder did little to help. Finally I went to a drug store to buy something to help. The pharmacist was very helpful. He explained that I had “jock itch” and that is was a fungal infection. He further said that the presence of fungi is not unusual, but with the right combination of moisture, warmth, and time the fungi causes an infection. The hot moist air, and me sweating constantly was promoting the fungal growth and infection. He also explained that people who are overweight get a similar rash, but it is more from skin rubbing on skin and against clothing – he called this chafing. Both result in similar results and pain. With either problem, loose clothing is best, especially fabrics that wick moisture away from the skin. Skin-tight shorts that wick under loose clothing often helps.
He suggested that I buy an off-the-shelf anti-fungal spray, after work each day shower and carefully dry all areas completely, and apply the spray. And it worked. Each morning the rash was gone and I felt as good as new. I would get a little discomfort towards the end of each day, but repeating the process daily made life bearable. And when the humidity decreased, the problem went away completely.
Chafing happens when the skin rubs against skin or clothing and there is a lot of perspiration or moisture in the affected area. Applying a lubricant such as Body Glide or similar along with a wicking base layer helps most people. If you are overweight, fix that problem first so your thighs or buttocks don’t rub against each other.
One problem backpackers have is keeping these hinter areas clean. Whenever possible a good daily (minimum) washing and drying is necessary. Since I am rather skinny chafing is never a problem. Hiking in hot, humid weather can be potentially by problematic. For this kind of weather, when I must wear long pants, I wear a pair of Ex-Officio Boxer Briefs along with a pair of Rail Riders Eco-Mesh Pants. The briefs wick away moisture and the mesh panels on the pants keep things ventilated, plus the pants have a generous cut and loose fit. Mostly I wear shorts when hiking. My favorites are Patagonia Baggies, which come with a brief liner and pockets to carry stuff. I cut out the liner so there is plenty of ventilation. When I don’t need pockets in my shorts, I wear Patagonia Field Shorts. Loose and plenty of ventilation with both of these shorts. Colin Fletcher’s Second Law of Thermodynamic Walking explains how this works: “Give your balls some air.”
Except the one time I experienced jock itch as an automotive technician I have never had a problem with chafing or fungal infection. And I don’t need to wash the hinterland daily when backpacking.