Some allergies are genetic although others appear as a result of something, like a switch. The organism doesn't like something and it creates a response (then it's not strictly an allergy). Perhaps this indicates that there's some sort of toxicity nearby and even you don't know it.
The interesting aspect is how this could lead to identify problems that without this response could be causing harm during years leading toward more substantial issues.
There are professionals who make tests of common activators, but for sure there are multiple substances that cannot be tested easily.
Anything that smells is a potential culprit, like paints, plastics, woods, glues, rosins, and for this line. Synthetic chemicals. VOC (Volatile Organic Compounds) are chemicals that dissolve into air, so with some cans of paint or glue in proximity, you could measure them with a meter. Same with some synthetic resins that fix wood fibers together. It looks harmful, but it's not; a simple piece of synthetic wood normally has formaldehyde. Plastics, mostly PVC carry phthalates, a toxic substance to make it flexible with a strong odor. This type of plastic is one of the most used around the world. Different countries have regulations and stay away of the problem. Others not, and permit the risks.
These are possible causes of a response, and with a simple solution: move them to another place where no one could receive a single molecule coming from these sources.