Nut allergies: When can a mild cough send you to hospital? UAE doctors explain how to spot danger

A single bite is all it takes.

A child suddenly rubbing their tongue after a biscuit. An adult breaking into hives after a restaurant meal. Swollen lips after a handful of nuts that never caused a problem before. A nut allergy often announces itself in ways that are easy to dismiss.

Dubai-based mum R. Pavithra recalls the first time her six-year-old son grabbed a handful of nuts. For around 15 minutes, he appeared fine and was playing with his friends. "I started hearing coughing, and it became more persistent. He kept drinking water, and said it was hurting. The coughing grew worse, and I knew we didn't have any time to waste," she says, remembering how they immediately rushed him to hospital. "He had to stay overnight, and since then, we have been so careful."

Nut allergies may be more ubiquitous than we realise. You don't always see a reaction coming; sometimes it seems to appear suddenly and escalate quickly. It's an immune reaction to nut proteins, affecting children and adults, with symptoms ranging from itching and hives to breathing difficulty and anaphylaxis.

For families, the real challenge is recognising the earliest signs, understanding how fast a reaction can turn dangerous, and cutting exposure risk at school, parties and at home.

So, we spoke to three specialists: Dr Rajashree Ganesh, Specialist Internal Medicine at Medcare Shaikh Saqr Al Qasimi Hospital; Dr Jaspreet Kaur, Specialist Internal Medicine at RAK Hospital; and Dr Mufaza.

What are the first signs of a nut allergy?

A nut allergy doesn't always begin with dramatic breathing difficulty. The earliest symptoms often involve the skin, mouth or digestive system, and look different in children versus adults.

As Dr Ganesh explains, the reactions vary from one person to another, and the symptoms can range from mild to rather severe. The early signs could include itching or tingling in the mouth, swelling of the lips, face or tongue, hives, redness of the skin, or stomach symptoms such as nausea, vomiting or abdominal discomfort. "Some people may also develop coughing, wheezing or difficulty breathing. In young children, the signs can sometimes be less obvious, so parents may notice sudden irritability, unusual tiredness, changes in behaviour or difficulty feeding," she says.

Moreover, symptoms that occur soon after eating or being exposed to nuts should be taken seriously, particularly, if more than different parts of the body are affected, she adds.

When it comes to young children, who might struggle to explain what they feel, Dr Kaur explains watching for irritability, rubbing the tongue, or scratching the ears. Adults, she notes, more often describe light-headedness, dizziness, a tightness in the chest, and can also faint.

When does a reaction become anaphylaxis?

The critical distinction is whether a reaction starts affecting the respiratory or cardiovascular system. Symptoms can appear anywhere from minutes to two hours after exposure, and in that window, a reaction can turn life-threatening.

"When the symptoms which started initially as hives, flushing, swollen lips, tongue start Involving the respiratory or cardiovascular system like bronchospasm, wheezing, reduced blood pressure, dizziness one should be alert it's likely to become life threatening," explains Dr Kaur. This, could lead ro anaphylaxis.

Anaphylaxis, a severe, potentially life-threatening allergic reaction, can develop rapidly, and doesn't require every possible symptom to appear. Warning signs include difficulty breathing, wheezing, swelling of the throat or tongue, dizziness, fainting, or a sudden drop in blood pressure.

Once anaphylaxis is suspected, it should be treated as a medical emergency: adrenaline given without delay according to the person's allergy action plan, with emergency help sought immediately after.

That speed is exactly why preparation matters. Dr Mufaza describes anaphylaxis as a systemic reaction that can cause severe airway swelling, bronchospasm and cardiovascular collapse, in extreme cases, progressing to cardiac arrest.

What should you do after accidental exposure?

For anyone with a known severe allergy and a prescribed adrenaline auto-injector, having a clear action plan is crucial. Dr Kaur stresses that suspected anaphylaxis requires immediate action:

Epinephrine (adrenaline) if accessible is the single most effective treatment for severe allergic reactions and anaphylaxis. It works within minutes to reverse life-threatening airway swelling, bronchospasm, and cardiovascular collapse. Immediately after giving epinephrine call emergency service," explains Dr Kaur.

“If any one of the severe signs like airway or breathing compromise like wheezing, shortness of breath, dizziness, lightheadedness, loss of consciousness, severe swelling of tongue, lips, throat - inject epinephrine right away!” she adds.

Dr Mufaza notes that while antihistamines may help mild symptoms, they might not treat anaphylaxis, adrenaline via auto-injector remains first-line. Anyone prescribed one should know how to use it, carry it consistently, and make sure family and teachers can too; trainer devices help everyone practise in advance.

If you have been prescribed an adrenaline auto-injector, speak to your doctor or allergy specialist about when and how to use it, and make sure you have a personalised emergency action plan. If you or your child develops symptoms suggestive of a severe allergic reaction or anaphylaxis, seek emergency medical help immediately. If an adrenaline auto-injector has been prescribed and is available, it should be used according to the person's emergency action plan rather than waiting for symptoms to become more severe.

Can a nut allergy suddenly appear after years of eating nuts?

Eating nuts safely for years does not mean someone cannot develop an allergy later in life. The immune system can change over time, and allergies may appear at different stages of life, explains Dr Ganesh.

The allergy develops, when the immune system first becomes sensitised to a nut protein and then reacts, when the person is exposed to it again. “Developing an allergy requires two steps: sensitization (the immune system misidentifies a nut protein as a pathogen and produces specific IgE antibodies) followed by clinical reactivity (subsequent exposure causes IgE-mediated mast cell degranulation), the most common pathway is cross reactivity," explains Dr Kaur.

People with conditions such as eczema or asthma, or a history of allergies in themselves or their family, may be at higher risk. In adults, factors such as alcohol, strenuous exercise, NSAID use and acute illness can also increase the likelihood or severity of a reaction.

However, there is no simple way to predict who will develop an allergy to nuts. Dr Mufaza says genetic factors and changes in the immune system may play a role, although the exact reasons are not always clear.

Peanuts and tree nuts are not the same

Many people assume a peanut allergy and a tree-nut allergy are interchangeable. However, that's a misconception. Peanuts are legumes; tree nuts include foods like almonds, cashews, walnuts, pistachios and hazelnuts.

As Dr Mufaza explains, peanuts and tree nuts are biologically different. A person can be allergic to peanuts, tree nuts, or both. Being allergic to one does not automatically mean that someone is allergic to every other nut.

That's no reason to experiment, though: There can be cross-reactivity between certain nuts, and there is also a risk of cross-contact during processing and preparation. For this reason, people with a confirmed nut allergy should have an individual assessment with an allergy specialist rather than deciding independently which nuts are safe to eat, she adds.

A 2019 study in the Annals of Allergy, Asthma & Immunology backs up both points. Surveying 258 peanut-allergic patients, researchers led by Dr Shahzad Mustafa found most could actually tolerate tree nuts, yet nearly 40% avoided all of them anyway, largely out of fear of cross-contact rather than a confirmed allergy. It's why doctors recommend specialist assessment over guesswork: plenty of people are avoiding nuts they could safely eat.

Why cross-contact matters

Even a trace of nut protein can be a problem. Small amounts transferred during food preparation, through a shared knife, cutting board or countertop, are enough to trigger a reaction in someone with a significant allergy.

And so, it essential to clean equipment thoroughly before it's used for someone with an allergy. Cooking or heating food does not destroy nut allergens. High heat denatures some proteins, but nut allergens remain structurally intact and fully capable of triggering anaphylaxis. Dr Kaur advises washing utensils and dishes in hot, soapy water or run them through a dishwasher, and washing hands with soap and water rather than relying on sanitiser, which doesn't remove the protein.

Labels deserve the same care every time, Dr Ganesh adds, since ingredients can change between purchases, and a "may contain" warning should factor into every allergy sufferer's personal risk plan.

Keeping children safe at school and parties

Avoiding exposure is a shared task.

As doctors explain, parents need to make sure the school or nursery is fully aware of the child's allergy, the symptoms to look out for and what action needs to be taken in an emergency.

Dr Kaur recommends a written Anaphylaxis Emergency Action Plan signed by the child's physician, along with at least two unexpired and prescribed auto-injectors in their original labelled boxes, and staff trained to recognise and respond. The children should be taught not to share or accept food without checking with an adult, and Dr Kaur suggests sending a nut-free treat from home that looks similar to what other children are eating, so the child doesn't feel excluded.

The same applies beyond the classroom, restaurants and hosts should be told in advance, not assumed safe.

Can children outgrow a nut allergy?

Some children may outgrow certain food allergies, but nut allergies are often more persistent than some other childhood food allergies, says Dr Ganesh.

A 2024 study from the Murdoch Children's Research Institute, published in the journal Allergy, followed 156 Melbourne infants with confirmed peanut allergy through to age 10. Two-thirds were still allergic by that point, and among those who did outgrow it, most had done so by age six. Rather than a single test at one point in time, it was the way certain antibody levels shifted over the years that best predicted who would grow out of the allergy and who wouldn't.

Whether an allergy has genuinely resolved can't be assumed, just because someone hasn't reacted recently. Doctors rely on clinical history, skin-prick testing and IgE blood tests , and also storage-protein testing, and selected cases, an oral food challenge under medical supervision. "Families should not attempt such a challenge at home because a reaction can be unpredictable," says Dr Ganesh, a caution Dr Mufaza echoes firmly.

For those who remain allergic, allergen immunotherapy offers carefully controlled exposure to reduce sensitivity over time, but it requires specialist supervision, can itself provoke a reaction, and doesn't guarantee a cure.