Peanut and Tree Nut Allergy: Symptoms, Causes, and Diagnosis

Peanuts and tree nuts are a common cause of food allergy in adults and children. A reaction can be mild, or it can progress to life-threatening anaphylaxis. Let's go through calmly what happens and how it is checked.

What peanut and tree nut allergy is and how they differ

A food allergy is when the immune system mistakenly reacts to food as if it were harmful. In this sense, a peanut is not a nut but a legume, yet on lists of the most common allergens it appears alongside tree nuts: walnut, almond, cashew, pecan, pistachio, Brazil nut. An allergy is not intolerance: intolerance mainly causes bloating and abdominal pain, and it is not an immune system reaction.

How peanut allergy manifests: from rash to severe reaction

Symptoms usually start within a few minutes to two hours after eating. These include hives and itchy skin, tingling or itching in the mouth, swelling of the face, lips, and tongue, vomiting and diarrhea, abdominal cramps, cough and wheezing, runny nose and sneezing, dizziness. In one person, reactions can differ each time — sometimes it all depends on the amount eaten. In rare cases, anaphylaxis develops: narrowing of the airways, severe shortness of breath due to throat swelling, a sharp drop in blood pressure, loss of consciousness.

What else can cause a reaction: almond, walnut, cashew, sesame, seeds, coconut

A reaction to almond, walnut, or cashew is a tree nut allergy, and a person may react to several types at once. Sesame allergy is also on the list of common food allergens. Allergy is possible to any food product. Peanut butter is also peanut, and a reaction to it is the same peanut allergy. Oral allergy syndrome can also occur: itching in the mouth and throat after raw fruits, vegetables, or nuts, usually not severe.

• Hives, itchy skin, swelling of the lips and face
• Cough, wheezing, shortness of breath
• Nausea, vomiting, abdominal pain, diarrhea
• Dizziness, weakness, feeling faint

Why allergy occurs and who is at risk

The exact cause is unknown. The chance is higher if you or close relatives have other allergies, asthma, or eczema, as well as due to heredity. Peanut allergy occurs in about 0.6% of Americans; among children in the US, Canada, Australia, and the UK — within 1.2–3.5%. Some children with a confirmed allergy eventually outgrow it — at least 20% according to one study.

How tree nut allergy is diagnosed

The doctor asks about symptoms, family history, and other allergies, performs an examination, and orders tests: a skin prick test, blood tests, an elimination diet, and an oral food challenge — the most accurate. A food and symptom diary helps. The diagnosis is made by a doctor based on the examination results.

When urgent help is needed and when to see a doctor

See a doctor if you suspect an allergy in yourself or your child: the doctor will decide whether a referral to a specialist is needed. Do not remove foods from the diet without consultation.

Suspicion of an allergy alone is not a reason to call an ambulance. Call 103 or 112 if the lips, mouth, throat, or tongue suddenly swell; breathing becomes rapid or labored, or suffocation occurs; the throat tightens and swallowing is difficult; the skin, tongue, or lips turn blue, gray, or pale; the person suddenly becomes confused, drowsy, or dizzy; someone has lost consciousness and does not wake up; a child has gone limp and is not responding as usual. Do not drive yourself to the hospital: explain the situation to the dispatcher, and they will tell you what to do.

This material is for reference: it helps you get your bearings but does not replace a doctor's consultation — if you suspect an allergy, it is best to discuss it with a specialist.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer