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.
Whether because of a labor agreement, fears for lost productivity or other reasons, companies often find it hard to reduce employee wages or salaries. For this reason, many (though far from all) companies elect to conduct layoffs rather than wage reductions when facing losses or lower profits. See also: Wage resistance.