Ringworm causes itchy red, scaly, patches that may appear like a series of rings on the skin. Originally, it was thought the infection was caused by a worm, thus the name but it is actually caused by a fungus. Ringworm is the common name for fungal infections named tinea.
Depending upon where in the body the rash appears, the name after the tinea denotes its location. Ringworm in the areas listed below are called:
Beard – tinea barbae
Body -- tinea corporis
Feet -- tinea pedis (also called athlete's foot)
Groin area -- tinea cruris (also called jock itch)
Scalp -- tinea capitis
Nails-- tinea unguium or Onychomycosis
Ringworm is an infection caused from dermatophytes, which are a type of fungus that live on the dead layer of keratin on the surface of the skin.
https://www.empowher.com/ringworm/content/ringworm-and-other-tinea-rashes