Perianal candidiasis is when there is a yucky fungus called Candida growing around your bottom area. Candida is a type of germ that can make your skin feel itchy, red, sore, and can make it hard to poop. It’s sort of like a tiny bug that likes to eat the skin and grow there. Sometimes it happens to grown-ups because they wear tight clothes, don’t dry off well after swimming or showering, or don’t clean themselves well after pooping. But sometimes, little kids can get it too if they don't wash themselves properly after pooping or if they wear diapers for too long. It might feel really uncomfortable and itchy, but doctors can help make it better by giving you some medicine that will make the Candida go away.