When my aging mother's elderly Chihuahua developed severe itchy skin, I took it home with me. After a trip to the vet and a prescription for Cushings disease, she was fine. But later, I developed what looked like ringworm on my skin. A trip to the dermatologist told me it was some type of 'ringoid' similar to ringworm. A steroid super cream was given to me to try. It failed. So, after a bit of research and experimentation, I developed a successful treatment plan of my own.
What I recommend is an application of a general anti-fungal solution in the morning (Fungi Nail) / Lotramin cream in the afternoon / and liquid extract Cats Claw at bedtime.
[I won't detail my arduous trial and error steps along the way. And if this combination doesn't work for you, then you might include TeaTree oil and/or Black Walnut tincture. Also understand that high blood sugar may complicate matters if you are diabetic.
Read up on "skin fungi".]