At what level of Scovilles does capsaicin produce skin irritation?

September 17, 2008 6:48 AM

At what level of Scovilles does capsaicin produce skin irritation?

I know this would obviously vary based on the individual and various other circumstances.

I'm looking for the concentration (which seems to be usually measured in Scovilles, though I suppose it could be measured in other ways) of capsaicin which, if left without being washed off, not merely a burning sensation but also a mild redness and inflammation.

While I know from my own experience that people can become accustomed to the oral "heat," does skin typically exhibit a progressive sensitization, desensitization, or neither?

posted by adipocere to health & fitness (17 comments total)

Well, this scale rates standard issue pepper spray at between 2 Million and 5.3 Million Scovilles, so from there I'd surmise you'd being to see redness and inflammation just above or below 2 Million Scovilles.
posted by Happy Dave at 7:07 AM on September 17, 2008

I peeled and seeded 3 pounds of Hatch green chiles the other day (Scoville 1000-2500 according to that link) and my knuckles we tingling and "warm" afterwards, but there was no redness or inflammation. I wasn't wearing gloves, but I wash washing my hands regularly -- it seems enough of it stuck to give a very mild irritation.
posted by sararah at 7:30 AM on September 17, 2008

I saw a person get lip blisters from eating the same food as me. It was damn hot, but not impossible for me to eat (I have had some stuff that is).

I've never gotten anything more than red lips like a Mentat (the movie, not the book or mini series).

I also know for a fact it depends on what skin you're talking about. I've touched my eyes after washing my hands multiple times and had them turn all red just from cutting up some peppers.

I read on one of the pepper sites that most people cannot make any distinctions of hotness once you get over 40,000, but that's eating them straight, not adding them to something.

Sounds like we need to run an experiment. Out of curiosity, you thinking of trying this?
posted by cjorgensen at 7:54 AM on September 17, 2008

I'm trying to figure out how to relieve redness/inflammation/irritation. As such, I was looking for a reliable way to produce it without causing damage (such as mechanical stimulation). Your basic "give the mouse a disease so we can see if we can cure it" experiment.

Granted, it's a purely symptomatic approach to the problem, and there could be a conceivable difference between irritation from mechanical stimulation and a chemical irritant, but I think this would be good enough for jazz.
posted by adipocere at 8:11 AM on September 17, 2008

It depends on the person. The more you are exposed to it, the more resistance your body has to it.
posted by jeffamaphone at 8:18 AM on September 17, 2008

I was looking for a reliable way to produce it without...

Just have the subjects shave with a crappy safety razor.
posted by jeffamaphone at 8:19 AM on September 17, 2008

jeffamaphone is right, there's not one particular 'level'. I use capsicum-containing muscle rubs, and while it gets hot, it feels good too. My roommate tried to beat me to death one day for putting the same stuff on her whanged-up shoulder. She immediately went red, ran straight to a shower to wash it off, and still got a pretty decent sunburn's worth of peeling from it.
posted by pupdog at 9:41 AM on September 17, 2008

I got a chemical burn on my tongue once from eating a raw pepper - it looked like a jalapeno, which I could eat with mild discomfort at that time.

The scar lasted for years.

As has been mentioned, it's a very specific reaction, person-to-person, and a standard "level of reaction" is no more reliable for skin than for pleasurable taste. One person's OMGItHURTS! is another person's "medium".
posted by IAmBroom at 10:03 AM on September 17, 2008

Capsaicin doesn't cause an inflammatory response, just local vasodilation. In high enough concentrations, it depletes substance P entirely and acts as a local anesthetic, as in the case of Zostrix brand cream, which is just topical capsaicin.

The idea that capsaicin could cause a 'chemical burn' is not accurate.
posted by ikkyu2 at 10:24 AM on September 17, 2008

I'd settle for vasodilation at the moment. I just need erythema, but I figured I wouldn't get too technical in my terminology.
posted by adipocere at 11:04 AM on September 17, 2008

interesting ikkyu2, we just assumed it was the capsaicin. Maybe it was the menthol stuff in the cream then. Now I have to do some testing on my roommate, if I can figure out how not to get hurt in the process...
posted by pupdog at 12:18 PM on September 17, 2008

My one little data point - got a (mild) nosebleed from washing and cutting scotch bonnet peppers.

Cook with peppers all the time. Do not eat much of them, myself. Like enough of them in my food to clear my head, but don't want to bite into them.

Have cousins who could happily eat a peck of unpickled peppers without batting an eye.
posted by Lesser Shrew at 10:45 PM on September 17, 2008

Capsaicin doesn't cause an inflammatory response, just local vasodilation. In high enough concentrations, it depletes substance P entirely and acts as a local anesthetic, as in the case of Zostrix brand cream, which is just topical capsaicin.

The idea that capsaicin could cause a 'chemical burn' is not accurate.
posted by ikkyu2 at 1:24 PM on September 17 [+] [!]

ikkyu2, everything you said made sense. Nonetheless, for days after I ate the pepper, my tongue hurt slightly, and when I finally thought to check it in the mirror, I saw a tastebudless swath about 1/2" long or so, in roughly the shape of a Star Trek Federation badge. That area was bald for years; it has finally receded into the textures of my tongue.

So, whazzup with that? Any guesses?
posted by IAmBroom at 6:05 AM on September 26, 2008

You probably should have been a little less vigorous in tonguing the joy buzzer of that Tasha Yar lookalike you met at the convention, IAmBroom.

Seriously, I don't know. You sure your tongue wasn't like that before you ate the pepper?

Birds lack substance P, or receptors for it. They can eat a habanero just as easily as they can an apricot, with no ill effects. To them, a super-hot pepper that would make you die is just a not-very-fleshy fruit.
posted by ikkyu2 at 6:19 PM on September 27, 2008

OK... but cjorgenson's anecdotal evidence agrees with mine. And so does pupdog's (in a less dramatic sense, but the skin was clearly still killed by the application).
posted by IAmBroom at 6:16 AM on September 29, 2008

(and, nope - my tongue was whole & pain-free prior to that. Can't swear it was perfect an hour before, and as I stated, it was days before I checked it in the mirror, but there was a REALLY noticeable new mark.)

Your comments about birds are interesting, but in the end irrelevant. Mice can eat poison ivy, because urushiol oil doesn't affect them. That doesn't mean that it won't cause blisters on humans.
posted by IAmBroom at 6:19 AM on September 29, 2008

Urushiol causes histamine release from mast cells. Capsaicin doesn't do that, it's a neurotransmitter analog. It's not a cytotoxin or irritant on its own. I don't know how many different ways there are to say that.
posted by ikkyu2 at 8:19 PM on September 29, 2008