Hi, Welcome to HCM. Rashes in areas where more sweating occurs is caused by fungal infection but not necessarily yeasts. Most common fungi causing such infection are dermatophytes or tinea. These infections are not hereditary. I suggest you get a fungal culture done of the skin scrapings from your rashes to confirm the pathogen causing infection. This test might take around two to three weeks. I suggest you get in touch with a dermatologist and get antifungal therapy prescribed based on the test results. Mind you, antifungal therapy needs to be continued for at least 6 weeks to 3 months. If treatment is not taken correctly, there is chance of recurrence of lesions. Maintenance of personal hygiene is a must and keep those areas clean and dry. Thanks.