It is a fact of life that we are constantly subject to external input from our environment. Daily, we touch, inhale, absorb and ingest substances that are all around us. We are inextricably bound to our environment throughout our lives and our bodies endeavor to maintain a state of health by fending off the many harmful substances we come in contact with.
Food allergies in particular are the result of a hypersensitivity to a protein in a food. The person’s immune system reacts to that protein as if a dangerous invader had breached the body’s defenses. Even though the food consumed is in itself harmless, the immune system perceives it as it would a virus or a bacteria and attacks it to eventually destroy it.
We are most familiar with food related allergies that crop up during childhood. Often times they resolve themselves as the individual matures. It is quite common that people who experienced sensitivity to certain foods can later consume them without exhibiting any adverse reactions. Of course, it is unfortunate that the opposite is also true: food allergies can stay with an individual and become a lifelong struggle.
What is Happening during an allergic reaction?
When a truly harmful substance enters the body it activates the immune system. We call any substance that brings forth such a reaction an allergen or antigen. The body responds immediately by creating proteins called antibodies. These entities are also known as immunoglobulins and are designed to bind with the foreign substance in order to keep the body from any damage. There are five different kinds of immunoglobulins, but type E (IgE) is the primary mediator in an allergic reaction.
When we first ingest any kind of offending food, the body creates an IgE antibody specific to the problematic protein in that food. Each allergen has then its own particular antibody and they are not interchangeable. Antibodies accumulate on mast cells or basophiles ready to come into action if the particular allergen is again detected. When we are repeatedly exposed to the offending food, the allergens rapidly bind with the antibodies and elicit the release of chemicals such as histamine. This is the moment when the allergic reaction takes place and it becomes outwardly noticeable to the patient. The parts of the body most widely affected are the skin, lungs, gastrointestinal tract and respiratory system simply because they have the largest concentration of mast cells and basophiles.
Those of us with persistent food allergies have at one time or another experienced many of the most common symptoms that ensue such as diarrhea, vomiting, stomach cramps, hives, itching and swelling. Even though they can be extremely uncomfortable, patients tend to recover from these episodes with no or little medical intervention. However, those most harshly affected can sometimes face a life threatening situation should the allergy develop into anaphylactic shock. Anaphylaxis is very serious and requires emergency care without delay. If the swelling affects the tissues in the throat area, breathing can become difficult and the life of the patient could be at risk. Always seek immediate medical attention for anaphylaxis.
Types of Allergic Reactions
In general, allergic reactions initiated by food fall into two categories: immediate or delayed.
Immediate reactions take place within two hours of eating the offending food. Most often, they appear suddenly with a sensation of general malaise, dizziness or irritation of the skin. A prickly sensation can sometimes be felt on the tongue or cheeks, and the symptoms will intensify as time passes. I have personally experienced instances during which I became almost instantly symptomatic after eating. My face and upper torso turned bright pink and a momentary pins-and-needles feeling on my jaw was the only clue at the onset of the episode. Some other times, a sudden ache at the pit of the stomach indicates the beginning of an allergic reaction for me. Other signs such as hives quickly follow and extreme tiredness can be my most lasting symptom of all.
Delayed reactions, on the other hand, are less common and more difficult to pinpoint. They can appear up to 48 hours after the ingestion of the offending food. They can result in eczema, urticaria or asthma and can be very elusive to diagnose since a large variety of foods can be consumed by the time any reaction is even noticeable.
Most Common Symptoms of Allergic Reaction
Symptoms and their severity vary depending on the individual. Still, the most commonly affected sites remain the skin, gastrointestinal tract and the respiratory system.
Negative reactions to food often present with hives in the face, neck and upper torso. Other parts of the body are also susceptible to rashes with or without raised bumps. Flushing can be generalized ranging from a mild blushing to a deep pink erythema accompanied by a sensation of heat.
Nausea and stomach cramping can be the first sign of a food allergy and should not be overlooked. Often times the symptoms evolve into episodic vomiting and bouts of diarrhea.
Persistent nasal congestion and rhinitis (nasal discharge) can appear as subtle symptoms of an allergy to a certain food. Sneezing and asthmatic symptoms are often accompanied by eye irritation and profuse tearing and although they are associated with other environmental triggers can also be caused by offending foods.
In addition, edema can result in very troublesome and painful swelling of the eyelids or mouth area. Less commonly but far more dangerously, it can affect and constrict the airways. Headache and dizziness can be present as well and the allergy sufferer can appear disoriented.
Any or all of these symptoms can occur in isolation or simultaneously. If severe, they can develop into a serious, life threatening case of anaphylaxis which could, potentially, put the life of the patient at risk.