How can you tell the difference between dry eyes from eye allergies? symptoms?

This is not obvious by questions asked. The symptoms overlap and a person may suffer from both low tear production & airborne eye allergies at the same time. The common clinical approach would be to use simple antihistamine eye drops on a trial basis for a week or so to see if it helped.

There are some characteristics of allergic reactions which also may be present and include swelling, itching and associated rash and rhinitis. A family history of allergies increases the likelihood of allergic eye conditions. Dry eyes may also be associated with redness but unlike allergic eye disease there is no excessive clear eye discharge.