I would first suspect the peanuts and peanut oil.  Very small
amounts of peanuts produce large results in people who are sensitive.
For this reason plain M&M list peanuts as an ingredient (according to The
Wall Street Journal) because the machine that makes them is next to the
machine that makes peanut M&M and dust landing on the plain ones could
cause a person who was sensitive to go into anaphylaxic shock and
die.

Cashews also contain a substance that causes inflamation similar to that
found in poison ivy.  Even cashews labeled as raw are blanched to remove
this substance, but small amounts remain and may cause a problem in some
individuals.

My own arthritis is trigerred by corn.  Even the corn starch used as a
binder in just two aspirin tablets will cause joint pain in my knees! A
can of Classic Coke (made primarily from corn syrup) is too painful to
consider on even the hottest Texas day!

Ray Audette
Author "NeanderThin:A Caveman's Guide to Nutrition"
http://www.sofdesign.com/neander