People are allergic to peanuts because their immune system mistakenly identifies peanut proteins as harmful invaders. When exposed to peanuts, this misidentification triggers an allergic reaction.
The Immune System's Role
The immune system normally protects the body from harmful substances like bacteria and viruses. However, in individuals with peanut allergies, the immune system overreacts to peanut proteins. This overreaction is a chain of events:
- Misidentification: The body identifies specific proteins found in peanuts as dangerous.
- Antibody Production: The immune system creates IgE antibodies specific to these peanut proteins.
- Sensitization: The individual is now "sensitized" to peanuts. This means that the next time they encounter peanuts, the IgE antibodies will be ready to trigger an immediate reaction.
- Allergic Reaction: Upon subsequent exposure to peanuts, the IgE antibodies bind to the peanut proteins, signaling mast cells and basophils to release chemicals like histamine.
- Symptoms: These chemicals cause a range of symptoms, from mild skin reactions like hives to severe, life-threatening reactions like anaphylaxis.
What Causes the Misidentification?
The exact reasons why some people develop peanut allergies are complex and not fully understood. Several factors are believed to play a role:
- Genetics: A family history of allergies increases the risk of developing peanut allergy.
- Early Exposure: Some theories suggest that the timing and method of early peanut exposure may influence allergy development. Some research indicates that early introduction of peanuts may reduce the risk of developing an allergy.
- Skin Barrier Dysfunction: Eczema or other skin conditions that compromise the skin barrier may increase the likelihood of developing food allergies, including peanut allergy.
- Hygiene Hypothesis: This theory suggests that reduced exposure to infections in early childhood can lead to an immune system that is more prone to developing allergies.
Symptoms of Peanut Allergy
Symptoms of a peanut allergy can vary from mild to severe and can include:
- Hives
- Itching or tingling in or around the mouth and throat
- Nausea
- Abdominal pain
- Diarrhea
- Vomiting
- Runny nose
- Shortness of breath or wheezing
- Anaphylaxis (a severe, potentially life-threatening reaction that can cause difficulty breathing, dizziness, and loss of consciousness)
Management of Peanut Allergy
Currently, there is no cure for peanut allergy. Management focuses on:
- Strict avoidance: Carefully reading food labels and avoiding foods that may contain peanuts.
- Emergency medication: Carrying epinephrine auto-injectors (EpiPens) for emergency treatment of anaphylaxis.
- Oral Immunotherapy (OIT): A treatment that involves gradually increasing the amount of peanut protein ingested under medical supervision to desensitize the individual. This is not a cure, but can increase the threshold for reaction.
Peanut allergy arises from an immune system malfunction that misinterprets peanut proteins as threats, leading to a cascade of allergic reactions upon exposure. Genetic predisposition, environmental factors, and early exposure history are thought to play a role in its development.
