Whether it is allergic rhinitis (runny, sniffly nose), asthma, food allergy or atopic dermatitis (skin rash), allergies run in families and few people understand it better than me. My mum and her mum before her had allergies, so I grew up over-reacting to invisible and often mysterious allergy triggers.
Luckily for me, the hypersensitivity took the form of sneezing and highly-treatable skin rash. So, I soon got used to going into paroxysm of sneezes as soon as I jumped into a pool, with the cold miraculously disappearing the moment I step out. The itchy rash some painkilling medicines made me break into just needed one dose of anti-allergy medicine to treat. Dust made me sneeze a lot too, and over time systematically destroyed the inner lining of my nose, making me impervious to strong smells, good or bad, which is a godsend living as I do in the hot, sweaty nation.
But in most people, allergies do more than trigger sneezing and rash. The number of people with more severe allergic conditions, such as asthma and acute food allergies that choke up their wind and food pipe, has doubled in the past decade. Some countries have recorded a sharper increase, with data from the UK’s Health and Social Care Information Centre showing allergy-related hospital admissions in the nation have risen 8% in just a year.
There is, however, growing evidence supporting the hygiene hypothesis that states that allergies can be delayed or prevented if a child is exposed to allergens, dust, animals and infections in early childhood. Exposure to bugs and other pathogens is essential to develop a healthy immune system that is not over-sensitive to things that are not life-threatening. It’s a bit like allowing your body to get used to multiple sources of food and water so that your guts don’t collapse if you have to eat in a place with suspect hygiene.
Early exposure to bacteria and animals protects children against wheezing, which is an early symptom of asthma, found US researchers who measured the frequency of wheezing and levels of exposure to five common inner-city allergens — cats, cockroaches, dogs, dust mites and mice — in children who had at least one parent with allergies. The study, which followed children from birth up to age three, found that exposure to cockroaches, mice and cats during the first year of life was associated with a lower risk of recurrent wheezing by age three.
They also tested whether bacteria, measured in house dust, influence asthma risk and found children with no wheezing or sensitivity to allergens at age three had higher exposure to allergens and a greater variety of bacteria, particularly those belonging to the Bacteriodes and Firmicutes groups, during their first year of life.
These observations support the emerging concept that early-life exposure to high bacterial diversity protect children from allergies. Most importantly, the findings show that this protection is even stronger when children also encounter high allergen levels during this period.
Food allergies are trickier and common ones — to cow’s milk, soy, egg, fish, shellfish, peanuts, wheat and tree nuts — are difficult to predict. Breast milk strengthens a baby’s immune system and is least likely to trigger an allergic reaction.
Restricting a mother’s diet during pregnancy and while breast-feeding have been tried as approaches to protecting against food allergies, but they haven’t worked. What has worked is stopping your children’s exposure to tobacco smoke before or after birth. Smoking — whether it is the mother smoking or inhaling secondhand smoke — during pregnancy increases the chance of her child wheezing during infancy and developing asthma and other chronic respiratory illnesses in later life.
If it’s just a sneeze, you can ignore it, but it’s a good idea to seek a doctor if your allergies are causing discomfort. Kits to identify triggers are online and over-the-counter allergy tests don’t work, warns the American Academy of Allergy, Asthma & Immunology (AAAAI). Allergy screening tests available online, applied kinesiology (allergy testing through muscle relaxation), cytotoxicity testing, skin titration (Rinkel method), provocative and neutralisation (subcutaneous) testing or sublingual provocation make it to the AAAAI’s highly avoidable list.