Thank you for your question Infections involving the genitals can be shared by sexual partners. That's why they are called sexually transmitted. However, infections often need testing and treating. Often it can be a simple yeast infection that thrives in dark, wet and warm places. Other times it can be more serious. Another point to consider if either of you have had unprotected sex with anyone else. Since this can be a sensitive issue and can complicate relationships it is better to seek professional help so no misunderstandings are created. If you have had such an episode its better to be upfront and both should get tested for currently known STDs. It is difficult to diagnose  skin related conditions without seeing them with your own eyes so it is important to show the doctor what you are seeing. That will help greatly with the diagnosis. Pl see a dr specialising in skin and DVD. hope this helps