How do symptoms of a true corn allergy usually differ from intolerance symptoms regarding timing and system affected?

Allergies are rapid and systemic; intolerance is usually delayed and gastrointestinal.

The critical differentiation between a true corn allergy and a corn intolerance lies in the body's reaction pathway and the resultant symptoms. A true allergy involves the immune system mistakenly attacking corn proteins, leading to rapid onset symptoms such as hives, itching, or swelling, which can quickly become systemic and life-threatening (anaphylaxis). Conversely, corn intolerance is a digestive issue, often involving the fermentation of resistant starch or reactions to phytic acid, resulting in delayed discomfort concentrated in the gastrointestinal tract, such as bloating or cramping. This difference in timing—rapid versus delayed—and scope—systemic versus localized GI distress—is key for individuals attempting to distinguish between the two adverse reactions.