Is your love of cheese giving you an upset tummy?

Not all reactions to food are a sign of an allergy, but can still have potentially life-threatening effects, as HELEN GILBERT (below) discovered when she developed histamine intolerance. AT LEAST three times a day, I look in the mirror and obsessively check my tongue. It’s not an attractive trait, but for the best part of 18 months, I’ve been contending with baffling allergic reactions that cause my tongue to swell hugely and my throat to tighten. The first episode put me in hospital — one of three dashes in four months — and struck out of the blue just three weeks after my 40th birthday. I’d had one glass of a fruit juice-based soft drink when I became aware of an odd, heavy sensation in my upper lip; a couple of hours later it had swollen enormously and I’d also developed an intolerable itching in my throat. I’d had dental work on a very painful tooth earlier, and assumed that my symptoms were related to the anaesthetic. But to be on the safe side, I called 111 for advice. The operator insisted on sending an ambulance. Thank goodness he did. When the paramedics arrived, they said I was having a severe allergic reaction and had to go to hospital: I refused, I’d never had allergies and didn’t want to take up a valuable NHS bed, but then my throat started to close up. I was pumped full of adrenaline twice — first in the ambulance, then later in the resuscitation ward, before being admitted overnight. Although I was diagnosed with anaphylaxis, a severe, potentially life-threatening allergic reaction, subsequent skin prick tests (for my suspected allergens, the fruit drink and anaesthetic), were negative, so I dismissed the episode as a freak event. But a few months later it happened again, this time after I’d eaten a green salad drizzled with balsamic vinegar. I took an antihistamine, but two hours later my tongue was so swollen it could barely fit in my mouth— the 999 operator struggled to understand me. After another hospital dash, followed by more skin prick tests (this time, for balsamic vinegar, halloumi cheese and pomegranate), the results were negative. By the summer, the reactions were happening almost every day, noticeably whenever I consumed Marmite, cheese, vinegar, lemons, limes, oranges and alcohol. After a third trip to hospital, I was given a comprehensive allergy plan of daily antihistamines to try to control my reactions, steroids in case they didn’t work and told always to carry an adrenaline pen. The doctors were unable to work out what was going on, but then I read about histamine intolerance (HIT), caused by an inability to metabolise the chemical histamine, found in certain foods. We all have a digestive enzyme in our gut called diamine oxidase which we need to break it down. The theory is that people with HIT have low levels, so the histamine builds up, leading to symptoms such as splitting headaches, rashes, itching and tummy pain after eating high-histamine foods. It is not an allergy as it doesn’t trigger so-called IGE antibodies, which react to proteins in an allergen: instead, it’s the high histamine levels themselves that cause the symptoms. As Amena Warner, head of clinical services at Allergy UK, explains: ‘Skin prick allergy tests on someone with histamine intolerance would come back negative because it’s the histamine in the food they’re intolerant to, not the protein.’ High-histamine foods include mature cheese, wine, beer and cider, cured meat, yeast, shellfish, sauerkraut, fermented soya products and most fish. Certain fruits, including citrus, grapes and strawberries, also release histamine. It’s not clear how many people are affected, because, as NHS England puts it, the condition is ‘non-specific’ — in other words it could be due to other problems,

although a 2007 paper in the American Journal of Clinical Nutrition suggested around 1 per cent of the population had histamine intolerance, 80 per cent of whom were middle-aged. Mainstream medicine is yet to be convinced by HIT — the problem, as one immunologist told me, is that there are few high-quality studies in this area. A very small 2015 study in the International Journal of Immunopathology and Pharmacology concluded that measuring the diamine oxidase activity in HIT patients could help identify those who would benefit from cutting back on histamine intake or taking a diamine oxidase supplement. And yet diamine oxidase testing is not available on the NHS partly because of lack of evidence for it. My own immunologist is yet to be convinced, but is supportive. Under his supervision I’ve been following a histamine exclusion diet for three months and my symptoms have improved remarkably. My last reaction, two weeks ago, came after eating crisps, which may have contained vinegar. But I’m no longer on daily antihistamines — I’ve also launched a blog charting my quest to relax in the hope it will calm my body down. For the first time in ages, I’m feeling hopeful . . . although it’ll be some time before I stop checking the size of my tongue in the mirror.