What should I do if an employee has allergy symptoms?

There is some overlap between common seasonal allergy symptoms and some of the symptoms that have been reported by people with COVID-19 (e.g., headache, sneezing, cough). It is important to take into account whether an individual’s symptoms are compatible with the usual symptoms and timing for allergy in that person.

No. Allergy symptoms are not considered an acute respiratory illness. However, there is some overlap between common seasonal allergy symptoms and some of the symptoms that have been reported by people with COVID-19 (e.g., headache, sneezing, cough). It is important to take into account whether an individual’s symptoms are compatible with the usual symptoms and timing for allergy in that person.

From the CDC's General Business Frequently Asked Questions