Tinea corporis (ringwom) is a fungal infection of the skin, most commonly found on the arms and legs (although can occur anywhere).
Like other forms of tinea (capitis or cruris) is identifiable by raised rings with erythematous edges and central clearing. It is itchy, and the edges are scaly. There is usually hair loss at the affected areas.
Treatment is with topical anti-fungal creams for three weeks, but oral anti-fungals may be needed for one week if topicals don’t work.
References
https://www.ncbi.nlm.nih.gov/books/NBK544360/
https://en.wikipedia.org/wiki/Tinea_corporis
https://www.webmd.com/skin-problems-and-treatments/picture-of-ringworm-of-the-body-tinea-corporis