London - When you tuck into those chocolate eggs this Easter, spare a thought for Louise McQuater. For even one tiny bite of chocolate could trigger her asthma and lead to a potentially life-threatening attack.
Most people think asthma is brought on by dust or pet fur, but there are many triggers for the characteristic coughing, wheezing, tightness in the chest and shortness of breath.
However, many of the 5.4 million Britons with asthma — and even some GPs — aren’t aware of these, and failing to identify and then avoid their more unusual triggers could put them at risk.
Indeed, Louise, 41, never thought chocolate was making her asthma worse until December 2012, when her asthma consultant suggested she looked at her diet after a number of attacks.
“I ate chocolate every day so thought it might be a trigger and started cutting down,” says Louise, a school learning assistant who lives with her three children in Tullibody, Clackmannanshire. “My asthma seemed to improve, although I still didn’t really believe chocolate was a trigger because I’d never heard of that before.”
But a terrifying experience a few months later made her realise it was.
She’d given in to temptation and bought her favourite chocolate bar, a Galaxy. After the first bite, she started coughing but finished it all because her craving was so bad.
Her coughing worsened and she was struggling to breathe — even a reliever inhaler, which relaxes the lung’s airways that can become inflamed in an asthma patient, didn’t help. She went to an out-of-hours emergency doctor, who put her on a nebuliser, which gives high doses of reliever medicine through a mask or mouthpiece, easing her symptoms.
“I was astounded chocolate caused that reaction,” she says. “Looking back, it’s possible it played a part in other attacks I’d had.”
Since then, Louise, whose severe asthma is also triggered by dust mites, hay fever and mould, has avoided chocolate.
Patients who don’t know all their triggers can risk asthma symptoms or attacks, says Deborah Waddell, clinical lead nurse at Asthma UK.
“Everyone’s triggers are different and can be difficult to identify. It can take people years to understand their asthma. Sometimes this can be because their triggers are more unusual, such as chocolate, wine or fizzy drinks,” she explains.
“Potential triggers are all around us. Health professionals need to be open-minded when patients report what they think makes their asthma worse.”
Patients’ airways become inflamed in response to irritant triggers such as exercise, stress or cold weather, or allergic triggers such as pollen or dust mites.
Irritants make vulnerable airways inflamed and narrow. This leads to contractions of the muscle of the bronchi (the main airway of the lungs), causing breathlessness and other symptoms. With allergic ones, the immune system goes into overdrive and sees the harmless substance, which can be inhaled or ingested, as dangerous.
An antibody, immunoglobulin E (IgE), looks for the allergen and signals to the immune system to produce powerful chemicals including histamine, which cause inflammation and swelling in airways.
Goblet cells, which produce mucus, are also set off. This results in thick, sticky mucus in the airways — one of the biggest problems during an attack is making huge amounts of mucus you can’t clear, explains Ms Waddell.
Allergic asthma is often seen in people with a family history of atopy (predisposition to produce high amounts of IgE), including hay fever, eczema and food allergy, she adds.
Triggers can be identified through skin-prick tests, where a tiny amount of the suspected allergen is injected into the skin. A red, itchy bump larger than 3mm appearing after ten minutes confirms allergic sensitisation to that substance, says Dr Ramesh Kurukulaaratchy, a consultant respiratory physician at Southampton General Hospital.
Blood tests are also used, when blood is mixed with allergens and checked for IgE. But these only look for specific allergens and can give misleading results.
For suspected food allergy triggers, patients can take challenge tests, ingesting small amounts of the substance under medical observation. “But access to allergy services is extremely limited across the UK,” says Dr Kurukulaaratchy. Some people find they have more triggers over time, while others may show a lessening of triggers.
However, Dr Kurukulaaratchy believes people whose asthma is triggered by certain foods such as chocolate are not having a true allergic response involving the immune system, but have been irritated by chemicals they contain known to aggravate some people’s asthma.
“Chocolate is rich in organic compounds called amines that can provoke allergic-type reactions in some people,” he explains.
There are natural and artificial chemicals in other foods and drinks that could be triggers — for example, alcohol has naturally-occurring amines and salicylates, and preservatives like sulphate, which are not commonly regarded as triggers, but can lead to symptoms.
Mother-of-one Christina Nicol discovered at 18 that vodka was a trigger for her, and needed her reliever when it left her unable to breathe. “Other types of alcohol don’t trigger my asthma but when I’ve tried vodka since, the same thing happened, so I avoid it,” says the hotel receptionist, now 38, from East Kilbride, South Lanarkshire.
Dr Kurukulaaratchy says salicylates (the active ingredient in aspirin) can be found in herbs, spices and mint — so even toothpastes and mouthwashes may lead to symptoms.
Samantha Rawlings, 30, had an attack after using her mother’s toothpaste instead of her own. “Within an hour of using it I was in hospital,” says the pub manager from Bristol. “The consultant said it was likely to be a chemical in the toothpaste.”
Unfortunately, there aren’t validated tests for substances that provoke chemical sensitivities, so recognising patterns is vital, says Dr Kurukulaaratchy.
Being aware of triggers can also help because there are additional treatments for allergic asthma. One treatment, approved for UK use last year, is Xolair, an injection which tackles IgE. “New treatments are being developed, so patients should receive more tailored treatment,” says Dr Kurukulaaratchy.
Drugs known as leukotriene antagonists, such as Singulair tablets, which block a chemical reaction that can cause inflammation in airways, can also be effective for allergic asthma, adds Dr Nazim Nathani, a consultant respiratory physician at BMI The Priory and City Hospital in Birmingham.
“As well as trying to avoid triggers, it’s crucial to take your preventer inhaler (containing steroids) daily to build up protection — this should reduce the effect of triggers,” says Deborah Waddell.
People with asthma should think carefully about what may be triggering symptoms, adds Louise. “They may need to think outside the box.” - Daily Mail