Food Allergy

Food Allergy
Specialty	Allergology
Symptoms	Hives, anaphylaxis, swelling, vomiting, diarrhea, breathing difficulties
Complications	Anaphylaxis, asthma
Causes	Immune response to food proteins
Risk factors	Family history, other allergies
Diagnostic method	Skin prick test, blood test, oral food challenge
Differential diagnosis	Food intolerance, celiac disease, inflammatory bowel disease
Prevention	Early exposure (in some cases)
Treatment	Avoidance of allergens, medications, emergency medication
Medication	Antihistamines, epinephrine

Food Allergy is a type of allergy resulting from an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives, or swollen airways. In some people, a food allergy can cause severe symptoms or even a life-threatening reaction known as anaphylaxis.

Causes

Food allergies happen when the immune system overreacts to a protein in food that is normally harmless. The body perceives this protein as a threat and triggers an immune response. Common foods that cause allergic reactions include peanuts, tree nuts, milk, eggs, wheat, soy, fish, and shellfish.

Symptoms

Symptoms of food allergies can range from mild to severe and include:

• Hives, itching, or skin rash
• Swelling of the lips, face, tongue, and throat or other parts of the body
• Wheezing, nasal congestion, or trouble breathing
• Abdominal pain, diarrhea, nausea, or vomiting
• Dizziness, lightheadedness, or fainting

Severe cases can result in anaphylaxis, a potentially life-threatening emergency that requires immediate treatment with epinephrine (adrenaline).

Diagnosis

Diagnosing food allergies can involve several tests:

• Skin prick test: Small amounts of suspected allergens are placed on the skin and the area is pricked to allow exposure.
• Blood test: Measures the immune system's response to specific foods by checking the amount of allergy-related antibodies in the bloodstream.
• Oral food challenge: Done under medical supervision, the patient consumes gradually increasing amounts of the suspected allergen.

Treatment

The primary treatment for food allergies is avoidance of the foods that trigger symptoms. In cases of accidental ingestion, treatments may include:

• Antihistamines to alleviate mild symptoms
• Epinephrine injections for severe reactions, which can be life-saving

Patients are often advised to carry an epinephrine auto-injector (such as an EpiPen) at all times.

Prevention

For some allergies, research suggests that early introduction of allergenic foods to infants might prevent the development of allergies. However, this approach should be discussed with a healthcare provider.

See also

• Allergic reaction
• Eczema
• Food intolerance
• Immunotherapy