My day job is as an analytical chemist who has done toxicology
research and currently works in the QA department for a firm which
manufacturers high-purity solvents.
What you have is an acquired sensitivity, to either the alcohol fumes
or whatever they used to denature the alcohol with. An acquired
sensitivity is something the body does, when it kind of reaches an
overload condition of something. The overload level and an overload
of what are personal, so that doesn’t help much.
There are half a dozen diferent thing that various manufacturers use
to denature ethyl alcohol. It is legally your right to request
something called a material safety data sheet (MSDS) from the
manufacturer. This should list all of the components, and this may
give you a clue what you are actually allergic to. You can then try
different manufacturers until you found one that used something
different, and try it.
Everclear is a possibility. It is 95% ethyl alcohol, with the other
5% being water. This will burn a little cooler, with a
slightlyyellow flame. Of course, you have to get it from a liquor
store that handles hard alcohol. And it is banned in Ohio (some
college kids did something stupid–and died from alcohol poisoning).
A cheap alternative might be methanol, or wood alcohol. It is
extremely toxic to drink (or to breathe a LOT of the vapor, not
likely in your situation), but that doesn’t seem to be your problem.
It almost certainly will not contain the denaturing substance (unless
the use methanol, a less common denaturant) and the heat generated
will be similar.
The amount of heat generated is an important consideration. Most
hydrocarbon solvents (like lamp oil) will be too hot to give
equivalent heat. Methanol, ethanol, and isopropanol (rubbing
alcohol) burn cooler than most other things that burn.
I need to weasel here a moment. I can’t guarantee that the above
will be safe for you. While reasonable precautions should make the
activity relatively safe, there are no guarantees.
How is your ventillation? From your symptoms, you could also be
reacting to low-levels of carbon monoxide. If the flame is any color
other than an almost invisible blue, you are experiencing incomplete
combustion, which can generate carbon monoxide.
At a guess, from the fact that you are using an alcohol lamp, I
suspect you may be working with wax or something similar. If this is
the case, you don’t really need a flame, just heat. A variable heat
heat gun with a focus cone may give you what you need. You will
probably have to play with settings, but it should work.