A food allergy occurs when the immune system reacts inappropriately to proteins in the food to which the person is allergic. Symptoms can be triggered by ingesting even minuscule amounts of the food. Most commonly, reactions occur within minutes of eating the food. Occasionally, they may occur a few hours after the exposure.
Food allergies most commonly begin in childhood. However, some people develop food allergy as adults to a food they have always eaten without problems. Certain food allergies that affect young children may be eventually outgrown. Some of the most common allergic foods are:
- Cow’s milk
- Tree nuts
Symptoms of Food Allergy
Food allergies can produce a wide range of symptoms in patients. These symptoms may be relatively mild and cause discomfort or be severe and even potentially fatal. Any time an individual experiences some form of allergic reaction, it is important to make an appointment with an allergist to determine the source of the allergy. The symptoms of a food allergy may include:
- Flushing, hives and itching of the skin
- Vomiting, abdominal pain and diarrhea
- Sneezing, runny nose, congestion and itchy or watery eyes
- Swelling under the skin or angioedema
In more severe cases, symptoms may include:
- Swelling of the throat and hoarseness
- Difficulty breathing, wheezing and chest tightness
- Dizziness or loss of consciousness
- Anaphylactic shock
- Fatal reactions
If an anaphylactic reaction occurs, emergency medical care should be sought immediately. Delaying treatment can result in death in some cases.
Diagnosis of Food Allergy
Many people who experience reactions to foods have intolerance rather than a true food allergy. For example, lactose intolerance from milk can be easily confused with milk allergy. Food intolerance frequently has similar symptoms to that of a food allergy, especially if there is gastrointestinal distress involved. However, people with food intolerance can often safely eat a small quantity of the problematic food without eliciting a reaction. In contrast, those with a true food allergy typically cannot consume any amount of the trigger food without developing symptoms.
Therefore, accurate diagnosis of true food allergies is important to prevent future allergic reactions. An allergist will be able to diagnose food allergies based on a combination of taking a complete history, skin testing and blood testing. Occasionally, an allergist-supervised food challenge may be required to confirm the diagnosis.
Treatment of Food Allergy
The most effective treatment option for food allergy is strict avoidance of the implicated food. It is very important to check ingredient labels for all food products to make sure they do not contain the allergic food. When eating at restaurants or at the homes of relatives or friends, always ask about the ingredients used.
For those patients who experience milder allergic reactions, an antihistamine may be an effective treatment method to relieve the symptoms. For individuals who tend to experience more severe reactions, immediate medical attention is required. An allergist will also prescribe injectable epinephrine that patients should carry with them at all times. This medication must be used in a timely fashion in case of a severe reaction.