Jock itch, or tinea cruris to the scientific community, is probably the most uncomfortable skin fungus. And keep in mind that although it typically affects males, women can get it, too.
This type of skin fungus is characterized by a rash developing around the groin, anus and inner thighs (however, the penis and scrotum are not usually affected). The center of the rash can get reddish-brown, while the edges develop scales or bumps. The skin gets scaly and will burn and itch. It may even develop blisters that ooze.
It's not uncommon for a person to develop jock itch after getting athlete's foot (which we'll talk about later). This could have to do with a fungus spreading by the process of putting on underwear -- so it's probably a good idea to put socks on first.
Typical treatments include topical creams, usually with one of two types of anti-fungal ingredients: allylamines or azoles. Allylamines will work faster, but are typically more expensive than azoles [source: Mayo Clinic].