A classic example of a feetishist, I'd say!
A man in China who reportedly sniffed his dirty socks each day learned the hard way that his habit is apparently a health danger.
The man, identified only as Peng ... reportedly developed a habit of sniffing his socks each day after work. But this unusual custom allegedly landed him in the hospital after the Zhangzhou resident complained of chest pains, tightness in his chest and a cough.
Initially, doctors at Zhangzhou's 909 Hospital suspected that Peng, 37, had pneumonia. But when his symptoms persisted, doctors re-questioned the man and he eventually admitted he was “addicted to smelling his socks that he had been wearing,” he said.
Physicians would later discover the man had a serious fungal infection in his lungs, more formally known as pulmonary fungal disease. The infection was likely caused when the man inhaled the fungal spores found in the dirty socks.
There's more at the link.
I wonder how one treats athlete's foot when it turns into athlete's lung? Or is that question too callus? And, since Peng likes sniffing his smelly socks, should his name be changed to Pong?