“Do Chinese lack sweat glands in their armpits?
Why does spicy food make you sweat?”
http://www.straightdope.com/columns/021004.html
I notice that I sweat on my cheeks, just under my eyes, whenever I eat cheese, particularly Cheddar. I’ve come to the conclusion that it must be caused by some reaction my body has to the sourness of the cheese, perhaps in combination with the aroma.
A clarification on Cecil’s comment about sweating after parotid surgery. I’ve recently had parotid surgery to remove a benign tumor under my ear, so I’ve had some opportunity to read up on this topic.
The occurance of sweating near the parotid is known as Frey’s Syndrome, and is developed by around 1/3 to 1/6 of folks who have parotid surgery. Frey’s basically happens because, as Cecil said, the healing facial nerves knit to the sweat glands in your skin, causing sweating near the surgery site during eating.
I’m told it takes 4-6 months to develop Frey’s after a parotid gland procedure, so I won’t know for some time if I’ll be enjoying this effect. I’m told that it’s mostly an annoyance, and I’d vote that it beats having a tumor. 
I have edited to fix the link — CKDH
I had always heard that the sour smell of sweat was from the bacteria eating away at it, not from the sweat itself. Do the smelly sweat glands just produce sweat with more proteins (or whatever) that the bacteria like to eat?
I use those crystal deodorants because regular antiperspirants make me itch like crazy (and regular deodorants just don’t work). I thought that the crystal works because it leaves behind minerals that don’t let the bacteria survive. In any case, it works exceptionally well as a deodorant - I still sweat, but it doesn’t stink (according to my wife’s radar nose).
Let’s try that again:
I dunno about sweating, but after eating slightly spicy food (chili, taco sauce) my nose runs.
My entire head seems to sweat from eating spicy food. It doesn’t seem to start gradually or in varying degrees either. It’s like there is some threshold that must be reached – either I sweat profusely from the food or not at all.
IIRC, the original purpose of spicy food was to make your face sweat. The sweat would evaporate, and cool you off. This is why cultures in tropical areas tend to have a lot of spicy foods. At least that was how they explained it on the PBS documentary on a jalapeño pepper contest.
saoirse, that doesn’t seem very logical. If it’s hot, you’re going to sweat anyway, with or without the peppers. If you don’t sweat, you’ve got serious troubles that a few jalapeños can’t cure. Makes as much sense to say curry gives you the runs, so that you have to drink more fluid, and that cools you down. Maybe the PBS folks know what they’re talking about, but it sure sounds suspicious.
Maybe people in tropical areas are sweating anyway, so they don’t notice the effect of the peppers. Or maybe peppers grow better in tropical areas, so people in tropical areas were more likely to incorporate them in their food. Kinda hard for an Inuit to make jalapeño blubber.
This site also supports it, but I can’t vouch for its reliability. It was linked to geometry.com, but isn’t anymore. I don’t know why.
It may be that the chiles (it seems that’s the correct term) cause more intense sweat, and therefore more intense cooling. That has certainly been my experience. I also read that the capsaicin causes the mouth to water, which aids in the digesting starches.