So nothing can be confirmed without examination. The standard therapy of erythrasma is antibiotics and antifungals because it is caused by a bacteria C minutissimum. Erythromycin is the drug of choice.
Mild steroids are helpful in reducing the inflammation associated with it. But use it only after a dermatologist’s prescription.
I hope it helps. Take care and please do keep me posted on how you are doing or if you have any additional queries. Kind regards.