Are other allergies, such as tree nut, milk, egg, wheat, or soy allergy, commonly associated with peanut allergy in patients with atopic diseases like asthma, eczema, or rhinitis?

Are Other Allergies Associated with Peanut Allergy?

Yes, peanut allergy is strongly associated with other food allergies, particularly tree nuts, and commonly coexists with atopic conditions including eczema, asthma, and allergic rhinitis.

Co-Existing Food Allergies

Tree Nut Allergy Association

• Peanut-allergic patients show 59-86% sensitization to tree nuts, with 33-34% demonstrating clinical reactivity 1
• Approximately one-third of peanut-allergic children also have clinical tree nut allergy 2
• Among tree nut-allergic patients, walnut, almond, and pecan are the most commonly implicated 2
• Higher specific IgE correlations exist between peanut and certain tree nuts, particularly almond and hazelnut 1

Critical caveat: Sensitization (positive testing) does not equal clinical allergy. Among peanut-allergic patients with no reported history of tree nut exposure, 50-82% showed IgE antibodies to specific tree nuts, but this does not necessarily mean they will react clinically 2. Oral food challenges may be needed to determine true clinical reactivity.

Other Legume Allergies

• Peanut-allergic patients demonstrate 19-79% sensitization to soy and other legumes, but only 3-5% show clinical reactivity 1
• When lupine (another legume) challenges were performed in peanut-sensitized patients, 28-30% reacted clinically 1
• Sensitization to lentils and chickpeas may indicate increased risk for multiple legume allergies 1

Multiple Food Allergies

• 30.4% of children with reported food allergy have multiple food allergies 1
• This may result from immune system hypersensitivity, cross-reactivity to structurally similar proteins, or increased testing in allergic individuals 1

Co-Existing Atopic Conditions

Eczema (Atopic Dermatitis)

• Severe eczema within the first 6 months of life is strongly associated with increased risk of developing peanut, milk, and egg allergy 1
• Food allergy and atopic dermatitis are highly associated conditions 1
• Infants with severe eczema and/or egg allergy have higher risk of peanut allergy 3

Asthma

• Asthma and food allergy frequently coexist in both pediatric and adult patients 1
• Children with food allergy have 4 times higher odds of having asthma 1
• Conversely, 44% of children diagnosed with asthma have an existing food allergy 1
• Food allergy is associated with severe asthma and may be a risk factor for severe asthma exacerbations 1
• Asthma is a critical moderating factor for severe allergic reactions and is associated with increased risk of fatal anaphylaxis from peanut 1, 4

Allergic Rhinitis

• The "allergic march" describes progression from atopic dermatitis in the first year of life to allergic rhinitis, asthma, and food allergy 1
• Patients with one atopic condition are predisposed to developing multiple allergic conditions 1

Clinical Implications for Risk Assessment

When evaluating a patient with peanut allergy, you must:

1. Screen for tree nut allergy - One-third will have clinical reactivity despite potential lack of known exposure 2
2. Assess for asthma - This is the most critical comorbidity as it increases risk of severe/fatal reactions 1, 4
3. Evaluate for eczema history - Particularly severe eczema in early infancy, which predicts food allergy risk 1, 3
4. Consider other food allergies - Particularly milk, egg, soy, and wheat, though clinical reactivity rates vary 1, 5

Important pitfall: Family history of atopy and presence of atopic dermatitis are risk factors for both sensitization to foods AND confirmed food allergy 1. However, sensitization alone without clinical symptoms does not constitute food allergy and requires clinical correlation 5.