Designed and created by Guideline Central in participation with the American College of Allergy, Asthma, and Immunology and American Academy of Allergy, Asthma & Immunology
Peanut Allergy Diagnosis
Objective
Objective
The purpose of this patient summary is to improve guidance about patient-centered care in the accurate diagnosis of an IgE-mediated peanut allergy, both in children and adults, so that an appropriate treatment plan can be developed.
This patient summary is intended exclusively for patients with an IgE-mediated peanut allergy only and not to peanut as a potential trigger in eosinophilic esophagitis or non-IgE-mediated food allergy such as food protein induced enterocolitis syndrome (FPIES).
Background
Background
Peanut allergies are among the most common food allergies, especially in children. They occur when the immune system mistakenly identifies proteins in peanuts as harmful, triggering an allergic reaction. This type of allergy is classified as an IgE-mediated allergy, meaning that it involves the production of a specific type of antibody called immunoglobulin E (IgE) in response to peanut proteins.
A person’s likelihood of having a peanut allergy can be influenced by several factors, including:
- Personal History:
- Previous allergic reactions to peanuts, such as hives, swelling, or difficulty breathing after eating peanuts or foods containing peanuts.
- Family History:
- A family history of allergies, particularly peanut allergies but also other food allergies, can increase the likelihood.
- Age:
- Young children are at a higher risk for developing peanut allergies.
- Other Allergies:
- Having other allergic conditions, such as eczema or asthma, may increase the risk of peanut allergy.
Peanut allergies can lead to serious complications which require immediate attention:
- Anaphylaxis:
- This is a severe, life-threatening allergic reaction that can occur quickly. Symptoms may include difficulty breathing, swelling of the throat, a rapid drop in blood pressure, and loss of consciousness.
- If you experience any of these symptoms, go to the emergency room immediately or call for emergency help.
- Allergic Reactions:
- Other symptoms can include hives, stomach pain, vomiting, and nasal congestion. While these symptoms can vary in severity, it’s important to take them seriously.
Diagnostic Tests for Suspected Peanut Allergies
Diagnostic Tests for Suspected Peanut Allergies
- Component testing:
- A type of allergy testing that looks for specific proteins in allergens, rather than testing for the whole allergen itself.
- For example, in peanut allergies, component testing can identify specific peanut proteins (like Ara h 1, Ara h 2, etc.) that may trigger allergic reactions.
- Ara h 2 testing:
- A type of component blood test that focuses on a specific peanut protein known to cause severe reactions. This test is highly specific for diagnosing peanut allergies.
- sIgE (serum immunoglobulin E) testing:
- A blood test that measures specific antibodies reacting to peanut proteins.
- SPT (skin prick test):
- A skin test where a tiny amount of peanut extract is placed on your skin and pricked.
- OFC (oral food challenge):
- Eating small amounts of peanuts under medical supervision to check for allergic reactions.
Evaluating a Suspected Peanut Allergy
Evaluating a Suspected Peanut Allergy
- Patients with a high likelihood of a peanut allergy are suggested to have diagnostic testing for a peanut allergy (through SPT or sIgE testing).
- Patients with a moderate likelihood of a peanut allergy should also have diagnostic testing (through SPT or sIgE testing) prior to doing an oral food challenge (OFC).
- Patients with a low or very low likelihood of a peanut allergy are not recommended to do diagnostic testing.
- If only performing one diagnostic test, the Ara h 2 test is suggested since it provides the most accurate diagnosis.
- Patients with a higher likelihood of having a peanut allergy may use Ara h 2, SPT, or sIgE to confirm the diagnosis of peanut allergy.
- Using component testing in addition to skin prick testing (SPT) or serum immunoglobulin E (sIgE) testing for whole peanuts is not recommended, since it does not necessarily improve the overall accuracy of diagnosing a peanut allergy when used alongside standard testing methods.
- It is not suggested to use results of a skin prick test, an sIgE test using whole peanut extract, or an sIgE test using peanut components as means of predicting how severe your allergy might be or how serious a future reaction could be.
Abbreviations
- FPIES: Food Protein-induced Enterocolitis Syndrome
- IgE: Immunoglobulin E
- OFC: Oral Food Challenge
- SPT: Skin Prick Test
- sIgE: Serum Immunoglobulin E