Hello! I have the exact same problem, although I do have some crusting and itching once in a while in the same place behind my right ear. What I do is when I shower in the morning, I take a pair of rough bath gloves, soap them up, and gently scrape away the dead skin.
When they are absorbed, they can be released in sweat through skin. Foods like yogurt, onions, garlic, red meat, cabbage, spices like coriander, and asparagus may result in increased body odor when consumed in large amounts. When you have a diet rich in proteins, you may have vinegar like smell on sweat.
What gives vinegar its distinctive smell? I ask because I opened a box of clothes at work today and got the smell of vinegar. It only seemed to be with the yellow coloured one so I was curious if what gives vinegar its smell could also be an ingredient in fabric dye.