A true food allergy is a abnormal response to a food triggered by a reaction in the body’s immune system and characterized by specific symptoms. The allergens responsible for food allergies are proteins that are usually resistant to heat from cooking, gastric acid and digestive enzymes. The symptoms of a food allergy begin within minutes of food entering the mouth to hours as food is digested and the allergens enter the bloodstream.
Tingling in the Mouth
A person with a food allergy can experience a tingling sensation in the mouth. The onset is immediate and may include itchy lips, tongue and throat. Sometimes, a person’s lips, tongue and throat may swell.
Difficulty Swallowing
This is the sensation that food is stuck in the throat or upper chest. It can be felt high in the neck or lower in the chest behind the breastbone.
Trouble Breathing
During an allergic reaction to food, a person may experience trouble breathing. As the allergens are absorbed and enter the bloodstream, they reach the respiratory airways. A person begins to wheeze as air flows through the narrowed airways.
Nasal Congestion
The sudden onset of a stuffy nose occurs because the membranes lining the nose become swollen. The blood vessels in the nasal mucosa become inflamed secondary to the allergic reaction. During an allergic reaction, histamine is released and causes inflammation.
Nausea & Vomiting
Once the offending food enters the stomach, a person feels nauseous. The person has the urge to vomit. Vomiting is the body’s way to remove the irritant food from the stomach.
Abdominal Pain
After the food is digested in the stomach, abdominal symptoms develop. Abdominal pain can be felt in the area between the chest and groin.
Diarrhea
Loose, watery frequent bowel movements are a symptom of a food allergy. Diarrhea is the body’s mechanism for expelling the allergen from the intestinal tract.
Hives
Hives are raised red welts that develop on the surface of the skin. Often itchy, these bumps are a symptom of an allergic reaction. With an allergic reaction, histamine is released causing itching and swelling.
Lightheadedness & Weakness
In some cases, a food allergy triggers a severe, life-threatening allergic reaction known as anaphylaxis. The immune system becomes sensitized to an allergen following initial exposure. A later exposure to the same allergen causes a rapid and severe reaction.
Anaphylactic Shock
Anaphylactic shock is a life-threatening condition caused by an allergic reaction. Blood pressure drops severely and vital organs are damaged because of restricted blood flow. Signs of anaphylactic shock include pale, cool and clammy skin, rapid but weak pulse, shallow breathing and loss of consciousness. Immediate medical attention is paramount.
Sources: MayoClinic.com: Food Allergy Symptoms
Health Professor: Food Allergy