Cashew Nut Allergy

Allergies to tree nuts such as cashew nuts are common in both children and adults and are often severe. Tree nuts include almonds, Brazil nuts, cashews, macadamia nuts, pistachios, pecans, walnuts, hazelnuts (and pine nuts classified as tree nuts in the US).

Cross-reactivity versus Co-reactivity

Cross-reactivity and co-reactivity is an essential concept to understand when dealing with nut allergies. People with tree nut allergies and peanut allergy frequently experience reactions stemming from various nut types.

For cashew nut the main related allergen is pistachio which is highly cross-reactive with cashew nut allergy. People with cashew nut allergy can also react to peanut and other tree nuts (such as hazelnut) that do not originate from closely related plant species.

People with cashew allergies have been shown to cross-react with other non tree-nut foods. The major cross-reactive foods are pink peppercorns (an increasingly common flavouring in crisps and crackers), sumac spice, citrus fruits and their pips (which often presents after drinking a smoothie where the pips have been included), peaches and plums, and mango and its seed. Talk to your doctor or allergy specialist if you’d like more information about cross-reactive foods.

Unlike many other tree nut allergies such hazelnut, almond and walnut, pollen allergy/hayfever are seldomly related to cashew nut allergy.

Products Containing Cashew Nuts

Cashews are often used as a substitute for pine nuts in pesto recipes. You can discover them in various sweet treats such as pastries, cakes, ice cream, and chocolates. Other products that may contain cashews include nut butters, nut oils, natural extracts, cashew nut milk and some alcoholic drinks.

It’s advisable to scrutinise food labels diligently, even if you’ve previously consumed a particular product. Food producers might modify ingredients or change manufacturing facilities, increasing the potential for cross-contamination.

It is not just food containing cashew that can trigger an allergic reaction, because cashew is found in non-food items too. Cashews and cashew byproducts are also found in makeup, bean bags, bird seed, cosmetics, hair care products, massage oil and lotions, and pet foods.

Always check cosmetic and toiletry labels for “Anacardium occidentale extract” and “Anacardium occidentale nut oil” on the label.

Symptoms of a Cashew Nut Allergy

Possible reactions, from least severe to most severe, can include:

  • Itching sensation in the mouth, throat, eyes, ears, skin, or other regions
  • Hives – local or generalised
  • Swelling in the lips, tongue, or face, also known as angioedema
  • Difficulty swallowing or hoarse voice
  • Sneezing, nasal congestion or a runny nose
  • Sensations of nausea, abdominal discomfort, vomiting, or diarrhoea
  • Wheezing or coughing
  • Breathlessness
  • Going pale, floppy or lethargic

It’s important to note that reactions to allergies can vary from person to person, and symptoms can range from mild to severe. If you suspect a cashew nut allergy, it’s crucial to consult with a healthcare professional for proper diagnosis and guidance.

Peanuts and tree nuts are responsible for the most severe food related allergic reactions, including life-threatening (anaphylactic reaction) or even fatal reactions.

Diagnosis and Testing

If you suspect your child might have a cashew nut allergy, it’s crucial to consult a doctor for proper allergy testing leading to allergy diagnosis and food allergy management. Skin prick tests are a common method used to determine whether a child is allergic to cashew nuts. Blood tests measuring IgE to cashew and the main allergenic protein Ana o 3 can predict likelihood of cashew nut allergy, but do not predict severity of reactions.

The gold standard for food allergy testing is the oral food challenge, which can be performed if there is uncertainty with the diagnosis or if the skin or blood tests indicate that your child has grown out of their cashew nut allergy. At Children’s Allergy Doctors, we can arrange an oral food challenge or supervised feed (in clinic) to confirm whether your child is allergic or tolerant to cashew nut.

Managing Cashew Nut Allergy

Upon receiving a diagnosis of a cashew nut allergy for your child, there are several precautions you can implement to ensure their well-being. Firstly, avoid eating cashew nuts and products containing forms of cashew nut.

Check food labelling carefully, as cashew nuts might be present in unexpected places. Following the introduction of Natasha’s Law, food businesses are now required to include full ingredients on pre-packed for direct sake foods. Reactions to nuts might also emerge due to concealed nut components or minute traces of nuts and specific seeds unintentionally incorporated during food processing or production.

Exercise vigilance when eating at restaurants and make sure to communicate your child’s allergy to the restaurant personnel. This step is crucial to avoid cross-contact (previously known as cross-contamination), where remnants of the allergen might be present in the food due to the sharing of utensils or food preparation areas.

It is commonly recommended to patients with any tree nut allergy to avoid all tree nuts; however, children with one nut allergy may go on to develop more nut allergies if this approach is taken. At Children’s Allergy Doctors, we recommend finding out which nut your child is allergic to and then introducing other nuts to prevent the development of further nut allergies.

Oral Immunotherapy for Cashew Nut

At Children’s Allergy Doctors, we are proud to offer Food Oral Immunotherapy (OIT) also known as Food Allergy Desensitisation, Oral Desensitisation (OD) or Food Desensitisation to cashew nut.

This is a process where you gradually introduce increasing amounts of the cashew nut into the child’s diet under supervision, to reduce the risk of allergic symptoms to accidental exposure to cashew nut and reduce severity of reactions, thereby reducing social restrictions and improving quality of life.

At Children’s Allergy Doctors, we offer cashew nut desensitisation in preschool children. The process takes 4-14 months depending on the cashew nut protocol your child is allocated to (which is personalised to their risk of reaction).

How can Children’s Allergy Doctors help?

Here at Children’s Allergy Doctors we provide a full range services for all allergy conditions. We aim to be with you every step of the way, from allergy diagnosis through to helping you with food allergy management and treatment.

Cashew nut allergies, like other food allergies, can be concerning for parents. Understanding the potential allergic reactions, cross-reactivity, and testing methods is essential for managing your child’s health effectively. With proper precautions and awareness, your child can lead a healthy and happy life, even with allergies.

If you would like to find out more about cashew nut allergy or any other aspect of children’s allergies, please contact our practice team on 0203 146 7721 or email


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