From the photo, the underlying cause of the rash is likely due to infected discoid eczema. Discoid eczema is a chronic skin condition that presents itself as itchy, coin-shaped patches to appear on the skin.
Ringworms which are due to fungal infections can be excluded by performing a simple laboratory test. This will allow us to check for any typical fungal features that may be present. It is best to visit a dermatologist to have a proper assessment so that he/she may choose the best-suited treatment to help with your condition.
With that said, the treatment for eczema may include a series of antibiotics and topical steroids. However, for the treatment of ringworms, it typically will include topical as well as oral anti-fungal medicines.