Nitrates are preservatives used in processed meat and fish to both enhance flavour and to prevent botulism. There is a small percentage of the population that is allergic to nitrates, and in some cases, the allergy is severe enough that it will cause them discomfort and even pain. The first step in diagnosing a nitrate allergy is being aware of the signs and symptoms that accompany it.
Headaches that routinely occur after the consumption of foods that contain nitrates can be a sign of a nitrate allergy. These headaches may be mild, or they may be severe. However, headaches can be caused by a wide number of different issues, and headaches alone do not point towards an allergy to nitrates.
Hives are outbreaks of red or pale bumps or welts on the skin. If you have a nitrate allergy, they can appear suddenly after consuming nitrates, and they may show up on any part of the body. Hives range in size from a pencil eraser to a dinner plate, and in most cases, they will subside in a few hours to a day.
Rhinitis is an inflammation or irritation of the nasal passages, and exposure to nitrates, when you are allergic to them, may cause a flare up. Sneezing, itching and a runny nose are all signs of rhinitis as is a feeling of blockage or congestion.
Asthma is an inflammation of the lungs or breathing passages; and though it is usually considered a chronic issue, the term also includes cases where asthma occurs due to an allergy. If you experience congestion in the chest, difficulty with breathing or coughing after you consume food with nitrates, it might point to a nitrate allergy.