Five things you think you might be allergic to – but aren’t

Seasonal symptoms like itchy eyes or throat, runny nose and sneezing are likely hay fever. If you have symptoms year-round, though, you may be dealing with nonallergic rhinitis.

While working as a junior doctor, Dr Sophie Farooque developed sinusitis and was prescribed penicillin. After Farooque came out in hives, a colleague told her she was clearly allergic to penicillin. Years later, she discovered she wasn’t and that an infection had caused the hives (your skin can release histamine to fight off infection).

A new study has discovered she’s far from alone. According to The Royal Pharmaceutical Society, millions of people mistakenly believe they’re allergic to penicillin, with researchers finding that over 90 per cent of those labelled with an allergy didn’t have one when tested.

Farooque is now one of the UK’s leading allergy experts and the author of Understanding Allergy.

“Drug allergy is a very real problem and can be extremely serious,” Farooque says. “However, another issue is the mislabelling of someone as allergic to a drug when they are in fact suffering from a side effect or symptoms of illness or infection.”

So, what might you not be allergic to after all?

Penicillin

According to The Royal Pharmaceutical Society, millions of people mistakenly believe they’re allergic to penicillin.

Adam Fox, Professor of Paediatric Allergy at King’s College London, says the new research “very much resonates” with his experience. “The issue of over-diagnosis of penicillin allergy is something I see all the time in my clinical practice,” he says, adding that the label can stick with somebody for a lifetime.

Yet, when you dig into their story, he continues, you often find the same thing: “They had an illness when they were very young, started antibiotics and developed a rash. In most cases, the rash was due to the infection the antibiotics were prescribed for rather than the antibiotics themselves. Numerous studies have shown only around 10 per cent of those labelled as penicillin allergic actually turn out to be. But ‘de-labelling’ them, in other words proving they aren’t allergic, often requires specialist testing.”

Dr Farooque agrees, and says that of all the drug allergy labels, this is the one that has the greatest potential negative impact. “Penicillin is an incredibly useful antibiotic. Therefore, patients are given alternative antibiotics, which may be less effective.”

The difficulty, she says, is that allergy testing is usually carried out in specialist clinics, which can be challenging for an under-pressure health system.

“You could request to see an allergy clinic on the NHS, and there are a fair few that focus on ‘de-labelling’,” says Professor Fox. “Or you could see an allergy specialist privately. In truth, access to either will vary geographically.”

Gluten

Studies show as many as one in 10 people avoid gluten. Photo / Young Shih, Unsplash

According to the British Dietetic Association, one in 100 people have coeliac disease, where your immune system attacks your own tissue when you eat gluten, which is a protein found in wheat, barley and rye. However, studies also show as many as one in 10 people avoid gluten.

“Never having had any gluten issues myself, I was pretty ignorant on the topic until several years ago when my mother-in-law was diagnosed with coeliac disease,” says nutritionist Sam Rice, author of Supercharge Your Diet. During her research, Rice discovered the over-60s are the largest demographic for diagnosis. “So, the first takeaway message is that you can develop coeliac disease at any age.”

Diagnosed by your GP, it’s caused by your body mistaking gluten for an alien invasion and producing antibodies to fight it, which damages the gut lining. “This leads to gut problems, weight loss and fatigue, and potentially long-term health issues such as coronary artery disease and small bowel cancer,” says Rice. “There is no cure and a gluten-free diet is the only treatment.”

Gluten intolerance can feel similar, but it’s not thought to impact longer-term health, there is no way to formally diagnose it, and it often involves an elimination diet under the supervision of a dietitian.

Then you have what Rice calls the ‘Lifestylers’: “A growing number of people cut out gluten for perceived health or weight-loss benefits, which has been reinforced by the popularity of low-carb diets. However, if you have none of the above conditions, there is absolutely no reason to do so.”

Dairy

"A lactose intolerance is when you don’t produce enough of the enzyme lactase, so you can’t properly digest the sugars in milk, leading to bloating and diarrhoea," says nutritionist Sam Rice.

“It’s a similarly confusing picture as with gluten,” says Rice on the rising number of people who avoid dairy in the belief they’re intolerant to it.

“A lactose intolerance is when you don’t produce enough of the enzyme lactase, so you can’t properly digest the sugars in milk, leading to bloating and diarrhoea. While a dairy allergy is an immune response to certain milk proteins leading to allergic symptoms such as swelling, hives, breathing problems and potentially anaphylaxis [a severe, life-threatening reaction, also known as anaphylactic shock, with symptoms such as a weak or rapid pulse, a raised, red skin rash, and swollen eyes, lips and tongue].”

Rice says intolerance is different to an allergy, which is easy to diagnose because symptoms are clear and immediate, so speak to your GP if you’re worried.

“Allergies are reportedly on the rise in general, but with lactose intolerance it’s harder to assess if it’s increasing as it has been a strong health trend to avoid dairy generally. And because there is no definitive test for intolerance, most incidents are self-reported and self-diagnosed.”

Cutting out dairy for no good reason isn’t wise, according to Rice, who says the nutrients in it, such as calcium and vitamin D, are important for bone, teeth, and heart health.

Fruit

There are two main types of fruit allergy: pollen fruit syndrome (PFS), and lipid transfer protein (LTP) allergy, which is more serious. Photo / 123RF

“Allergists often see patients with suspected allergies to fruit,” says Farooque, who says there are two main types: “The milder form is called pollen fruit syndrome (PFS) and the more severe form is lipid transfer protein (LTP) allergy, named after the type of proteins in fruits, vegetables, nuts, seeds and cereals that cause a reaction.”

Farooque says the first is a reaction to the proteins found in raw fruits, vegetables, some tree nuts and soya, which are similar in structure to proteins found in certain pollen (such as birch or grass). “When some people who have hay fever eat those foods, their immune system gets confused and thinks they are munching a mouthful of pollen,” she says.

Reactions are usually mild, such as an itchy mouth, lips or ears, swollen lips, a slightly tight, itchy, uncomfortable throat or sneezing. “Cooking or canning the food usually destroys the cross-reactive protein, so a patient who reacts when eating a peach will be fine with tinned peaches.”

LTPs are found in all fruit, nuts, seeds and vegetables. But unlike PFS, cooking the food doesn’t eliminate the allergy and people with LTP allergy are at risk of more severe allergic reactions, including anaphylaxis.

“Meanwhile, some foods are notorious for irritating the skin and causing redness, especially in children, including strawberries and tomatoes. This is often mistaken for food allergy, but these are unlikely allergens,” Farooque says.

According to British research, only 2 per cent of people have a fruit allergy, so it’s important to remember the abundance of health benefits of fruit, which is full of fibre and vitamins.

Pollen

One in four people in the UK suffer from hay fever.

One in four people in the UK suffer from hay fever, which Farooque points out leads to more than 4 million sick days worldwide and costs the British economy £300 million (about NZ$609m) a year in lost productivity.

“One study of UK teenagers with hay fever found they were 40 per cent more likely to drop a grade between their mock and final exams than peers who did not have hay fever,” Farooque says. “And this rose to 70 per cent if they were taking a sedating antihistamine treatment.

“Seasonal symptoms, like itchy eyes, throat, or inner ear, watery eyes, an itchy, runny nose and sneezing that respond well to allergy treatments are likely to be hay fever.”

However, if symptoms are year-round then it’s probably not a pollen allergy, but rather nonallergic rhinitis, where symptoms include a blocked or drippy nose and sneezing. This has no clear cause, but can be triggered by dust or other irritants. Treatments include saline nose sprays or antihistamines.

What’s the difference between an allergy and an intolerance?

According to Allergy UK, intolerances are more common, don’t involve the immune system and aren’t life-threatening. They can take several hours or longer to show symptoms, which may include skin problems such as eczema, bloating, and IBS symptoms. The only diagnosis is an elimination diet under the care of a medical professional.

An allergy, on the other hand, does involve the immune system. Farooque says this is because an allergy causes your immune system to respond to something harmless that it thinks is harmful. Symptoms of an allergy are immediate and include itching, sneezing, hives, and even anaphylaxis.