Hi, Sorys. The way to know that is to websearch for--> dermatophytosis DDx
That leads to a long list like this:
However, I'd first look at this:
which says that presentation can vary a lot.
Best of all might be to try various OTC antifungal topicals.
It's not impossible for you to get a fungal infection in those areas, but highly unlikely. Fungus likes hidden moist areas. It's most commonly going to be found where you sweat and don't dry, such as the sides of your feet if you're athletic, between the toes (athlete's foot), the groin. And it looks like a red rash and it itches -- man, does it itch. I'd go see your doc and if your doc can't diagnose it he or she will send you to a dermatologist. Have no idea what it is -- could be moles, could be skin tags, but as they are asymptomatic, again, not likely to be fungus, which definitely has symptoms. But when you get a new growth, especially if it changes in color or shape over time, see a doc.