Help Me Diagnose My Friends Hair Por Favor

[g.i joey]

So my friend has had troubles lately with what looks like a random bald patch in the middle of his head, basically where the sides meet the midscalp on one side is completely bare spot. He has no history of hairloss and still maintains a FULL head of hair with no other signs of male pattern baldness or hairfall. Its about the size of apenny his bald spot and he has been using nizoral for about 2 weeks with no benefit. Have any of you guys heard of this or can put a name to it? If you need any more info let me know, besides pics, i dont wanna take a pic of my friends bald spot, and at the same time he doesnt know im on HairLossTalk.com.