1 Pain that does not diminish with rest, and pain that may be worse at night than during the day. 2  Back pain along with constitutional symptoms, such as loss of appetite, unplanned weight loss, nausea, vomiting, or fever, chills or shakes.
Unstable chemicals. Onions produce the chemical irritant known as syn-propanethial-S-oxide. It stimulates the eyes' lachrymal glands so they release tears. Scientists used to blame the enzyme allinase for the instability of substances in a cut onion.
Onion Allergy Symptoms. Allergic reactions to onions can be internal or external. External reactions usually result from direct contact or smelling onions, while internal reactions come from ingesting onions. An individuals response or allergic reaction may show up at different times and at varying degrees.