Hello And welcome to Ask A Doctor service. I have reviewed your query and here is my advice. Perhaps it is either Pityriasis Versicolor Or Erythrasma. I request you to kindly visit a dermatologist in your vicinity for a confirmation of diagnosis. Pityriasis is a yeast infection which favors the trunk and it presents as reddish brown blotches/ patches of various sizes. The infection favors areas such as the chest and torso. The condition is asymptomatic or mildly itchy and single dose of an oral antifungal like either Fluconazole or Itraconazole is usually effective. Erythrasma, on the other hand is a bacterial skin infection caused by corynebacteria. It presents as asymptomatic brown patches in body folds like groin, axilla and submammary areas Treatment includes oral antibiotics like either erythromycin or doxycycline along with topical clindamycin. Hope I have answered your query. Let me know if you need any more assistance.