Food allergies can sometimes kill and the fact was perhaps best highlighted in Dan Brown’s bestselling thriller, Da Vinci Code, in which the chief villain murders his allergy-prone sidekick by spiking the cognac with peanuts to cause a fatal allergic reaction called anaphylaxis.
This reaction makes it hard for the person exposed to an allergen to breathe, and in some rare cases, the condition deteriorates so fast, the person dies.
This, however, seldom happens, as people with violent reactions to food allergies rarely step out without life-saving drugs called epinephrine that can stop the allergic reaction.
Conveniently for fictional murderers, the victims never know that quick treatment can save their lives and they die violently when faced with a murder weapon as improbable as a peanut.
More cases of food allergies are being reported across the world and researchers have been unable to explain why. “Allergic reactions are highly unpredictable.
The symptoms and severity of the reaction vary from diarrhoea to shortness of breath, fainting and anaphylaxis,” says Ishi Khosla, director, WholeFoods.
People can develop food allergies at any time of their lives, even as adults. Arpana Jha, 55, collapsed twice — once in the street — and had to put in the ICU, where they discovered the reason was mild allergy to milk. "I knew about the allergy but had inadvertently consumed cake which had milk in it," says Jha.
Contrary to popular belief, natural foods cause the most allergic reactions, but some chemical preservatives and additives in food such as the yellow colouring tartrazine, sulphites, benzoates, salicylates, monosodium glutamate (ajinomoto), caffeine and aspartame may also cause reactions in some.
Milk protein, egg white, wheat, soya bean and fish cause most allergies in children. In adults, nuts, including peanuts, almonds and walnuts, and seafood such as fish, crab, prawn and shrimp are common allergens.
An immediate allergic reaction that in volves the immune system is more worry ing as it can cause a generalised rash, itch ing, swelling of the throat and tongue, dif ficulty in swallowing or speaking, alter ation in heart rate, asthma, abdominal pain, nausea, vomiting and sudden drop in blood pressure.
The person may faint. Peanut anaphylaxis is caused by traces of food being absorbed in the mouth or intestine, leading to rapid release of histamine from cells causing allergic tissue swelling.
People with food allergies should always be careful about what they eat and drink, especially at restaurants where allergens may be well hidden when used as ingredients in some dishes.
"As far as possible, always carry your medication — antihistamine, asthma inhaler, epinephrine — check the ingre dients or ask what all has gone into the making of the dish," says Khosla.
Food allergy can be diag nosed by skin-prick tests to var ious foods or by RAST (radioal lergosorbent test). “Correct diagnosis is important as some al lergies such as those caused by wheat may predispose people to other disorders like type-1 diabetes mellitus, autoimmune liv er disease, thyroid disorders, asthma; ulcerative colitis, and an increased risk of cancer of the intestine,” says Dr Neelam Mohan, consultant paediatric gastroenterologist at Ganga Ran Hospital.
Skin testing with fresh food extracts is more accurate. If no food can be identified, but an allergic reaction is strongly suspected, two to three weeks of an elimination diet route is followed. The person lives on a limited number of foods, which are unlikely to cause allergies, such as potato and rice.
Once the allergic symptoms settle, foods are slowly reintroduced one at a time to identify the offending food. This should be done under the supervision of a dietician as a child can end up malnourished on a prolonged few-food diet.
Children usually outgrow allergies to milk, eggs, soybean products and wheat, but rarely outgrow allergies to nuts, fish and shellfish.