"Pine mouth" syndrome: cacogeusia following ingestion of pine nuts (genus: pinus). An emerging problem?

We report a case of cacogeusia, specifically metallogeusia (a perceived metallic or bitter taste) following pine nut ingestion. A 36-year-old male presented with cacogeusia one day following ingestion of 10-15 roasted pine nuts (genus: Pinus). Symptoms became worst on post-exposure day 2 and progressively improved without treatment over 5 days. There were no other symptoms and physical examination was unrevealing. All symptoms resolved without sequalae. We contemporaneously report a rise in pine nut-associated cacogeusia reported online during the first quarter of 2009, and a significant rise in online searches related to pine nut-associated cacogeusia (or what the online public has termed "pine mouth") during this time. Most online contributors note a similar cacogeusia 1-3 days following pine nut ingestion lasting for up to 2 weeks. All cases seem self-limited. Patients occasionally describe abdominal cramping and nausea after eating the nuts. Raw, cooked, and processed nuts (in pesto, for example) are implicated. While there appears to be an association between pine nut ingestion and cacogeusia, little is known about this condition, nor can any specific mechanism of specific cause be identified. It is not known if a specific species of pine nut can be implicated. "Pine mouth" appears to be an emerging problem.