The term ‘nut allergy’ can be confusing, because we tend to use it to describe an allergic reaction to the fruit of unrelated plants such as peanuts, seeds and nuts that grow on trees. Peanuts are related to chickpeas and peas, whereas tree nuts include almonds, cashews, macadamia nuts and walnuts. Seeds include sesame seeds, sunflower seeds and coconuts.
Peanut allergy is one of the most common allergies in children and although the allergy will improve with time for some, for others it will become worse. People who are allergic to peanuts will not necessarily be allergic to tree nuts or seeds.
Symptoms of peanut, tree nut or seed allergies vary and range from milder reactions to a severe allergic reaction (anaphylaxis). The most common symptom of a nut allergy is raised red bumps of skin (hives) and other allergic symptoms such as runny nose, cramps, nausea or vomiting. The best way to manage peanut, tree nut and seed allergies is to avoid all products containing these foods.
Food allergies can be life threatening and peanuts, tree nuts and seeds are some of the most common food triggers for life-threatening severe allergic reactions. If you, or a child in your care, have a severe allergic reaction (anaphylaxis), call triple zero (000) for an ambulance. Do not stand or walk . Administer adrenaline (epinephrine) via autoinjector (EpiPen®), if available.
Symptoms of nut allergies
Each person’s immune system is different and peanut, tree nut and seed allergies can cause diverse signs and symptoms, ranging from mild to severe. Many food allergies do not cause severe symptoms, but they can be life threatening in some people and should be taken seriously.
Some people have negative or adverse reactions to food (such as headache or bloating) that are not caused by allergies. These can be caused by factors such as food poisoning, toxic reactions or food sensitivities (intolerance). Although these are not allergic reactions, they are often mistaken for allergies.
Mild allergic symptoms that can occur before a severe allergic reaction include:
- raised red bumps of skin – hives (urticaria)
- swelling of the lips
- tingling of the throat and mouth
- itchy skin and rash
- runny nose
- tightening of the throat
- digestive symptoms – cramps, stomach pain, nausea or vomiting.
If you or a child in your care have experienced any of these symptoms after eating peanuts, tree nuts or seeds, the risk of having a severe reaction after eating that food is greater than usual. Ask your doctor to refer you to a clinical immunology or allergy specialist.
Keeping a record of your nut allergy symptoms
Diagnosing an allergy can be difficult. If you think you or a child in your care might have an allergy, keeping a record of symptoms can help you and your doctor to understand what is causing them.
Keep a diary that describes the symptoms, and when and where they occur. Your diary could include information about whether the symptoms occur:
- inside your home, outside or both
- for a short time or longer
- at night, during the day or when you wake up
- after you have had a particular food or drink
- after you have taken a herbal medicine.
Severe allergic reaction – anaphylaxis
Peanuts and tree nuts are among the most common foods to cause severe allergic reactions. Severe allergic reaction (anaphylaxis) is life threatening.
Symptoms of a severe allergic reaction include:
- difficult or noisy breathing
- swelling of the tongue
- swelling or tightness of the throat
- difficulty talking or a hoarse voice
- wheeze or persistent cough
- persistent dizziness or collapse
- paleness and floppiness in young children.
If you, or a child in your care, have a severe allergic reaction (anaphylaxis), call triple zero (000) for an ambulance. Do not stand or walk . Administer adrenaline (epinephrine) via autoinjector (EpiPen®), if available.
Causes of nut allergies
For all allergies, the immune system reacts to specific allergy trigger molecules (allergens). Your immune system, or that of a child in your care, produces antibodies that detect the allergen and cause inflammatory reactions and the release of a chemical called histamine. Histamine causes hives, hay fever and other allergic symptoms.
The molecules that trigger your allergic reaction can be present in a range of foods, and you may have an allergic reaction to foods containing that molecule. For this reason, some people are allergic to the same allergy trigger in cashews and pistachios. This is known as cross-reactivity. Speak to your doctor about cross-reactivity because it is difficult to predict.
In addition to peanuts, a wide range of tree nuts can also cause allergic reactions in some people. These include, but are not limited to:
- brazil nuts
- hickory nuts
- macadamia nuts
- pecan nuts
- pine nuts
The most common type of seed allergy is to sesame, although other types of seed, such as sunflower and poppy seeds, can also cause allergies. Allergic reactions to eating coconut, a large seed, are rare. However, an allergic reaction (contact dermatitis) caused by contact with coconut, and cosmetics and products containing coconut, is more common.
Peanut, tree nut and seed allergies are difficult to predict, so visit your doctor for an accurate diagnosis.
Diagnosis of nut allergies
If you have allergic symptoms, visit your family doctor who will ask some questions about your allergic reactions. You can also discuss your record of your symptoms. To diagnose your allergy, your doctor may refer you to a specialist doctor known as an allergist or clinical immunologist.
Allergists can test for allergies using a number of methods, depending on the type of potential allergy. To test for an allergy to peanuts, tree nuts and seeds, the allergist might:
- do a skin prick test
- do a blood test
- ask you to temporarily avoid all nuts or products containing nuts (elimination diet), then follow up with the introduction of nuts back into your diet (food challenge) under strict medical supervision.
Unproven methods to test for allergies
A number of methods claim to test for allergies but have not been medically or scientifically proven. They can be costly and could lead to dangerous avoidance of certain foods. The Australasian Society of Clinical Immunology and Allergy (ASCIA), the organisation representing allergists in Australia, recommends that you do not use certain methods to have potential allergies tested. These methods include:
- cytotoxic food testing
- electrodermal testing
- hair analysis
- pulse testing
- Vega testing.
Always speak with your doctor if you are thinking of using a complementary medicine or therapy to test for allergies.
Treatment for nut allergies
The only treatment for food allergies is to avoid the food that causes your allergy. Even if you are careful, it is difficult to avoid all contact with a specific food.
If you are at risk of a severe allergic reaction and you have been prescribed an adrenaline (epinephrine) autoinjector (such as an EpiPen), ASCIA recommends that you have an action plan for anaphylaxis. If you are not at high risk and have not been prescribed an adrenaline autoinjector, ASCIA recommends that you have an ASCIA action plan for allergic reactions.
To assist with food avoidance, people with food allergies need to become familiar and comfortable with reading food labels. ASCIA has fact sheets to help you understand how to read food labels and what to avoid if you have a peanut, tree nut or seed allergy.
Inaccurate diagnosis can lead to expensive and ineffective treatments, and unnecessary food avoidance, which can lead to malnutrition and food aversion, especially in children. Always speak to your doctor about your food allergy diagnosis and treatment options.
Emergency treatment for severe allergic reactions
If you are at risk of a severe allergic reaction (anaphylaxis), carry an adrenaline autoinjector such as EpiPen® and a means of calling for medical assistance such as a mobile telephone.
Emergency responses for a severe allergic reaction are:
- lay the person flat – do not allow them to stand or walk
- administer adrenaline with an autoinjector (such as an EpiPen®)
- always dial triple zero (000) to call an ambulance in a medical emergency.
If you are at risk of a severe allergic reaction, make sure you:
- have a severe allergic reaction action plan
- carry an adrenaline autoinjector (such as an EpiPen®) to treat a severe allergic reaction
- wear medical identification jewellery – this increases the likelihood that adrenaline will be administered in an emergency
- avoid medication (where possible) that may increase the severity of allergic reaction or complicate its treatment – such as beta blockers
- seek medical advice.
Where to get help