nut allergy

A nut allergy is a severe food allergy that affects approximately 0.5 to 1% of the U.S. population, making it one of the nine most common food allergies [1]. Tree nuts, which include almonds, Brazil nuts, cashews, hazelnuts, pecans, pistachios, and walnuts, are the primary culprits behind this allergy [2].

The symptoms of a nut allergy can range from mild to life-threatening. Mild symptoms may include minor itching, watery eyes, and a scratchy throat, while severe reactions can cause anaphylaxis, a potentially life-threatening condition that impairs breathing and can send the body into shock [3][4]. Other symptoms may include abdominal pain, cramps, nausea, vomiting, hives (urticaria), skin rashes, itching of the mouth, throat, eyes, skin, or any other area, stomach cramps, diarrhea, nausea, or vomiting, and stuffy nose [5].

It's essential to note that a nut allergy is not related to coconut allergies, which are rare and distinct from tree nut allergies. Most patients with a tree nut allergy are not allergic to coconut, unless they have a specific allergy to it [6].

Nut Allergy Signs and Symptoms

A nut allergy can cause a range of symptoms, from mild to severe. Here are some common signs and symptoms:

• Skin reactions: Hives, redness, or swelling on the skin [1]
• Digestive problems: Diarrhea, stomach cramps, nausea, or vomiting [2][3]
• Respiratory issues: Shortness of breath, wheezing, or coughing [4][5]
• Anaphylaxis: A severe, life-threatening allergic reaction that can cause difficulty breathing, swelling of the tongue, throat, or lips, and loss of consciousness [6][7]

Other symptoms may include:

• Abdominal pain or cramps
• Itching of the mouth, throat, eyes, skin, or other areas
• Stuffy nose or congestion
• Dizziness or fainting

It's essential to seek medical attention immediately if you experience any of these severe symptoms. If you suspect a nut allergy, consult with your doctor for proper diagnosis and treatment.

References:

[1] Context 1: Peanut allergy signs and symptoms can include skin reactions... [2] Context 3: Tree nut allergy symptoms include abdominal pain, cramps, nausea, vomiting, diarrhea... [3] Context 4: Symptoms · Hives (urticaria) · Skin rashes · Itching of the mouth, throat, eyes, skin, or any other area... [4] Context 5: Symptoms of a nut allergy include dizziness, itchy skin, swelling, wheezing, coughing... [5] Context 6: Symptoms of a nut allergy include severe allergic reactions (anaphylaxis), difficulty breathing... [6] Context 7: Symptoms may include impaired breathing, swelling in the throat, a sudden drop in blood pressure... [7] Context 9: Symptoms of a nut allergy can range from mild to severe. For some, exposure to even trace amounts of nuts can be life threatening...

Diagnostic Tests for Nut Allergy

Nut allergies, including peanut, tree nut, and seed allergies, can be diagnosed using various tests. The most common diagnostic tests for nut allergy are:

• Skin Prick Test (SPT): A small amount of nut-based solution is introduced into the skin, and the size of any resulting skin reaction (wheal) is measured. This test has a low rate of false negative results [9].
• Blood Test: A blood test can measure the levels of specific IgE antibodies in response to certain nuts. This test is often used in conjunction with other tests to confirm a diagnosis [5].
• Oral Food Challenge (OFC): This is considered the most accurate diagnostic test for food allergy, including nut allergy. However, it involves consuming small amounts of the suspected allergenic food and can be time-consuming and labor-intensive [7].

Other Diagnostic Tests

• Component Testing: This involves testing for specific components of nuts, such as proteins or enzymes, to determine if an individual is allergic to a particular type of nut.
• Sensitivity and Specificity: The sensitivity and specificity of these tests are important in determining their accuracy. For example, the 2020 JTFPP peanut allergy diagnosis GRADE guideline derived positive and negative LR's for skin prick testing (SPT), sIgE, and component testing [15].

Limitations of Diagnostic Tests

• False Negative Results: Some diagnostic tests, such as SPTs, have a low rate of false negative results that fail to identify a true allergy.
• High Costs: Some diagnostic tests, such as component testing, can be expensive and may not be covered by insurance.
• Limited Number of Components: Some diagnostic tests may only test for specific components of nuts, which can limit their accuracy.

Accurate Diagnosis

Accurate diagnosis using minimally invasive diagnostic tests is important in predicting clinical nut allergy. This can help identify those with potentially life-threatening reactions and enable less restricted diets and increased food choices for individuals with nut allergies [13].

Oral Immunotherapy (OIT) for Nut Allergy

There are several drug treatments available for nut allergies, including oral immunotherapy (OIT). OIT is a treatment that involves taking small amounts of the allergenic food, in this case, peanuts, to build up tolerance and reduce symptoms.

• PALFORZIA: This is an FDA-approved treatment for children ages 4 to 17 years that can help reduce the risk and severity of allergic reactions to peanuts, including anaphylaxis. It involves taking a daily dose of peanut protein powder under the tongue.
• Xolair (omalizumab): This is an antibody treatment that has been approved by the FDA for use in patients with severe food allergies, including nut allergies. It works by blocking the action of IgE antibodies, which are responsible for triggering allergic reactions.

Other Treatments

While these treatments show promise, it's essential to note that they may not be suitable for everyone and should only be used under the guidance of a healthcare professional.

• Sublingual immunotherapy (SLIT): This is another type of OIT that involves placing a small amount of peanut protein powder under the tongue. It has been shown to be effective in reducing symptoms in some patients.
• Antihistamines and epinephrine: These medications can help alleviate symptoms during an allergic reaction, but they do not treat the underlying allergy.

References

[1] FDA approves drug to treat severe food allergies, ... (Context 3)

[2] PALFORZIA is the first and only FDA-approved oral immunotherapy to help reduce the severity of allergic reactions to peanuts, including anaphylaxis, (Context 4)

[3] What types of peanut allergy immunotherapy are available? Peanut oral immunotherapy (OIT) is the most common peanut allergy treatment. The U.S. Food and Drug Administration (FDA) has approved one peanut allergy treatment. Other products and methods of peanut allergy immunotherapy are being studied. (Context 5)

[4] Aug 20, 2024 — Antibody treatments for peanut allergy include omalizumab (Xolair). Being prepared for a reaction. The only way to prevent a reaction is to ... (Context 6)

The differential diagnosis for nut allergy involves considering other conditions that may present with similar symptoms. According to various sources [3][7][8], the following are some possible differential diagnoses:

• Another food allergy: Such as egg, milk, wheat, soy, and sesame seeds [3]
• A drug reaction: Certain medications can cause allergic reactions or intolerance, which may be mistaken for a nut allergy [7]
• Acute urticaria: A condition characterized by sudden onset of hives or itchy skin, which can be caused by various factors including food, cold temperatures, or insect bites [4][8]
• Food intolerance: Conditions such as lactose intolerance or gluten sensitivity may present with similar symptoms to a nut allergy [4][7]
• Oral allergy syndrome: A condition that occurs when the immune system reacts to certain proteins in raw fruits and vegetables, which can be mistaken for a nut allergy [4]

It's essential to note that these differential diagnoses are not exhaustive, and a thorough medical evaluation is necessary to accurately diagnose a nut allergy. A healthcare professional will consider the patient's medical history, symptoms, and test results to determine the most likely cause of their condition.

References: [3] What is the differential diagnosis for peanut allergy? · Another food allergy (such as egg, milk, wheat, soy, and sesame seeds) [4] Differential Diagnosis. Acute urticaria. Food intolerance (e.g., lactose intolerance). Toxic reaction (e.g., scombroid poisoning). Oral allergy syndrome. [7] by K KUROWSKI · 2008 · Cited by 115 — Differential Diagnosis for Symptoms Suggestive of Food Allergies. Suspicion of food allergy begins with reports of symptoms that appear to be ... [8] Differential diagnosis. Contact skin reaction – erythema and/or urticaria occurring on any areas of skin in contact with the food, more commonly around a ...