All peppers are in the same family, and they all have capsaicin, just to
varying degrees, from zero down to the hottest pepper in the world which is
1 million Scoville units. 

So maybe it's just the higher amounts of capsaicin you are allergic to. 
Otherwise, I can't see any reason why you can eat one but not the other.  

Some peppers have no heat at all like the paprika pepper, or green garden
peppers.  Some peppers get hotter the longer they hang on the plant.  Some
have natural mild heat and some have flame heat.  And people's version of
what a chili pepper is, is different in each part of the country.  What one
area calls chili peppers, others will call by specific names in other areas.
 Here we have a large variety of hot peppers ranging from slightly mild to
the wild chili pequin, which is hotter than the habs, from jalepenos,
poblamos, habs, etc (I'm sure I've spelled them wrong).  

Samala,
Renee

-------Original Message-------

I have a question for the 'pepper people'... What is the difference between a 
chile pepper and a cayenne pepper?  I've been told I'm allergic to cayenne but 
chilies are OK.  I haven't come up with an explanation so I would appreciate 
any help.