Can allergies make you feel lightheaded and almost fainting i feel queasy?

Not likely: This is not expected in allergic diseases unless you are in the midst of an anaphylactic shock. Sometimes chronic sinusitis related to chronic nasal congestion may cause lightheadedness.

Queasy allergy: This would not be a typical allergy symptom but similar feelings may accompany other allergy symptoms. Abdominal cramping nausea or diarrhea and light headedness could be signs of an acute systemic allergic reaction to foods, bites, or sting anaphylaxis. Get a check up many things can cause these symptoms and it may be difficult to tell without an exam and possibly even a few tests or lab tests.