Peanut allergy

Overview

Peanut allergy is a condition where your immune system overreacts to peanuts, treating them as harmful. This can cause symptoms that range from mild (like a rash) to severe and life-threatening (called anaphylaxis). Peanut allergy is different from a food intolerance — it involves your immune system and can be dangerous.

Yes, peanut allergy is common. It affects about 1–2% of children in Western countries and many adults. The number of people with peanut allergy has been rising in recent decades.

Peanut allergy often starts in early childhood, but it can develop at any age. It affects both boys and girls, and people with a family history of allergies (like hay fever, asthma, or eczema) are more likely to have it. It is also more common in people with other food allergies.

Symptoms

Common symptoms

• Hives (red, itchy bumps on the skin)
• Swelling of the lips, face, tongue, or throat
• Itching or tingling in the mouth
• Nausea, vomiting, or diarrhoea
• Stomach cramps
• Runny or stuffy nose

Symptoms in children

• Skin rashes like eczema flare-ups or hives
• Sudden fussiness or crying (from discomfort)
• Pale or flushed skin
• Wheezing or noisy breathing
• Complaints of a 'funny feeling' in the mouth

Symptoms in older adults

• Symptoms can be more severe because older adults may have other health conditions
• Dizziness or lightheadedness (from a drop in blood pressure)
• Rapid heartbeat
• Feeling faint or passing out

Causes

Main causes

• The immune system mistakenly sees proteins in peanuts as harmful and releases chemicals like histamine to fight them
• This release of histamine causes the symptoms of an allergic reaction

Risk factors

• Family history of allergies (such as eczema, asthma, or other food allergies)
• Having another food allergy
• Early exposure to peanut through broken skin (like eczema) may increase risk
• Genetics — some people are simply more prone to allergies

When to see a doctor

See a doctor urgently if:

• After any severe reaction (trouble breathing, swelling, fainting) — seek emergency care immediately
• If you have used an adrenaline auto‑injector (epinephrine), you still need to go to the emergency room afterwards

Book a routine appointment if:

• If you or your child has a mild reaction (like hives) after eating peanuts, make an appointment with your GP or an allergy specialist
• If you suspect a peanut allergy for the first time, even without a clear reaction, see a doctor for testing

Diagnosis

A doctor will take a detailed history of any reactions and ask about your family allergy history. They may then recommend tests to confirm the allergy. Never try to test for peanut allergy at home by giving peanuts — that can be very dangerous.

Tests that may be done

• Skin prick test: a small drop of peanut protein is placed on your skin, which is then lightly pricked. If you are allergic, a raised red bump appears within 15–20 minutes.
• Blood test (specific IgE test): measures the level of allergy antibodies (IgE) to peanut in your blood.
• Oral food challenge: under strict medical supervision, you eat small increasing amounts of peanut to see if a reaction occurs. This is the most accurate test but is only done in a hospital setting.

What to expect at your appointment

Your doctor will explain the results and help you understand what they mean. If you are diagnosed with peanut allergy, you will be given a personalised action plan. This includes instructions on avoiding peanuts, recognising symptoms, and using emergency medicine if needed.

Treatment

There is no cure for peanut allergy, but it can be managed. The main treatment is strict avoidance of peanuts and peanut‑containing foods. For severe allergies, you will also be prescribed an adrenaline auto‑injector to use in emergencies. Recent research has shown that some people may benefit from oral immunotherapy (OIT) under medical guidance, but this is not a routine treatment for everyone.

Self-care at home

• Always read food labels carefully — peanuts can be in sauces, baked goods, candies, and many processed foods.
• Inform friends, family, and school or workplace about your allergy.
• Wear a medical alert bracelet or carry an allergy card.
• Check ingredients at restaurants and ask about cross‑contamination in kitchens.
• Carry your emergency medication (adrenaline auto‑injector) with you at all times.

Medical treatments

If you have a severe peanut allergy, your doctor will prescribe an adrenaline auto‑injector (like an EpiPen or other brands). This is a device that delivers a shot of adrenaline into your thigh during a severe reaction. You will be taught how and when to use it. Some people may also take antihistamines for mild symptoms, but these cannot stop a severe reaction. Oral immunotherapy (gradually exposing you to tiny amounts of peanut under medical supervision) is a possible treatment for some people, but it is not suitable for everyone and carries risks. Always discuss with your specialist.

When is surgery considered?

Surgery is not used to treat peanut allergy.

Living with this condition

Living with peanut allergy means being extra careful about what you eat and what is around you. You will need to read labels every time you buy food, since ingredients can change. Eating out requires asking detailed questions about ingredients and cross‑contamination. Many people find it helpful to carry safe snacks and be ready to speak up about their allergy. With practice, these steps become routine.

Lifestyle tips

• Plan ahead for meals, travel, and social events.
• Teach family and friends how to use your emergency medication.
• Create an allergy action plan with your doctor and keep it handy.
• Consider wearing a medical ID bracelet.

Diet and exercise

You can eat a healthy, varied diet that avoids peanuts. Focus on whole foods like fruits, vegetables, lean proteins, and grains. Always check labels for hidden peanut ingredients. If you are using oral immunotherapy, your doctor will give you specific diet advice. Exercise itself does not affect peanut allergy, but exercise can sometimes trigger a reaction if you have eaten peanuts recently — ask your doctor about this.

Mental health and emotional wellbeing

Living with a food allergy can be stressful and worrying. Fear of an accidental reaction may cause anxiety, especially in children and their parents. It is normal to feel frustrated or isolated. Talking to a counsellor or joining a support group can help. Remember that you can still do most things others do — with a bit of extra planning.

Prevention

Peanut allergy cannot be completely prevented, but research shows that for babies at high risk (like those with severe eczema or egg allergy), introducing peanut‑containing foods early — around 4 to 6 months of age — can lower the chance of developing peanut allergy. Always talk to your doctor before trying this, as it must be done safely.

Vaccines

There is no vaccine for peanut allergy.

Screening programmes

Screening for peanut allergy is not routinely done. If you have a family history of allergies, discuss your concerns with your doctor. They can advise if testing is appropriate, especially before introducing peanut to a high‑risk infant.

Complications

If left untreated

• Anaphylaxis — a severe, whole‑body allergic reaction that can cause trouble breathing, a drop in blood pressure, and loss of consciousness. This is a medical emergency and can be fatal if not treated quickly.
• Chronic anxiety or stress from the constant worry about accidental exposure.
• Nutritional deficiencies if you avoid too many foods without proper guidance.

Long-term outlook

With good management, most people with peanut allergy live long, healthy, and active lives. You can go to school, work, travel, and enjoy social events. The key is to stay informed, carry your emergency medication, and work closely with your healthcare team. Many children outgrow peanut allergy, and new treatments continue to be developed. You are not defined by your allergy — it is just one part of your life.

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