Allergies are the result of a hypersensitive immune system. The allergic immune system misidentifies an otherwise innocuous substance as harmful, and then attacks the substance with a ferocity far greater than required.
Laying off an employee is different from firing an employee. Firing means letting a worker go for any reason, whereas a layoff refers to an employment termination based on economics, usually involving more than one worker.
The difference between being fired and laid off California. At my old job, the head of Quality Control called me and told me that a friend was recently let go. While I liked the guy, working in QC and being very picky about errors and mistakes, I dont blame them for firing him.