Red wine contains naturally occurring histamines and sulfites, and both of these substances can cause reactions in sensitive people. However, despite the possibility of allergy-like symptoms, such as a runny nose, itchy or watery eyes, congestion, rash and itchy skin, reactions to red wine normally fall under the category of food intolerance rather than food allergy. When you have a true allergy, your immune system is involved. The allergenic protein in what you eat is registered incorrectly by your body and, as a response, your immune system releases an antibody called immunoglobulin E to combat the allergen. Then chemicals, including histamine, are released and you suffer the symptoms.

So when you ingest the small amounts of histamine present in red wine, your body might react as it would if it had released the histamine itself. However, your immune system isn't involved in the process. Similarly, people with asthma are particularly prone to nonallergic reactions to the sulfites in wine.