What do peanut bans, an unhealthy gut, Caesarean births and sterile homes have in common? All can increase the possibility of children developing allergies — which are rising in South Africa — and parents can often influence these risks.
A major new trial in the US proves, for example, that feeding at-risk children peanut products regularly from infancy to age five dropped the rate of peanut allergy in adolescence by 71%.
By age five, the risk of peanut allergy was reduced by 81% among the children given peanut products. A follow-on study showed this protection lasted “no matter how often kids eat peanuts in later childhood”. The results, published this week in the New England Journal of Medicine Evidence, contradict the advice parents were given for decades to avoid peanuts.
Prof Mike Levin, University of Cape Town (UCT) head of paediatric allergology at the Red Cross War Memorial Children’s Hospital, said: “The problem is many doctors still believe that avoiding allergenic foods early in life prevents food allergy, whereas the reverse is true. Also parents are scared to introduce allergenic foods to their babies particularly if they, or their other children have a food allergy.”
Eczema, food allergies, drug allergies, insect allergies, asthma and allergic rhinitis as well as a myriad different rashes are among the allergy-related conditions Cape Town paediatrician and allergist Prof Claudia Gray treats at the Kidsallergy Centre.
“Parents are usually most bothered by conditions which are either potentially life-threatening, such as food allergies, and those which severely affect the quality of life and the quality of sleep, for example eczema,” she said.
Allergies are rising in South Africa and globally. Levin said an increase in food allergies has taken place later but over less time than the increase in skin and respiratory allergies.
Eggs are the most common food allergen in children aged one to three, followed by peanuts and milk, he said, cautioning however that data on this in older children and adults was lacking. Food allergies among older children and adults include peanuts, tree nuts, fish and shellfish “though almost any food protein can be an allergen for some” said Levin, who has treated unusual ones.
“The problem is many doctors still believe that avoiding allergenic foods early in life prevents food allergy, whereas the reverse is true.
— UCT professor Mike Levin, head of asthma & allergy
A faulty or dysfunctional microbiome — the microorganisms in the gut — can disturb the immune system causing reactions such as allergies, which are essentially inflammatory conditions said Gray.
Modern diets, lifestyles and urbanisation contribute to this, while vaginal births, exclusive breastfeeding, lots of skin to skin contact for babies and healthy skin can reduce their allergy risks.
She said: “Other factors which play a role in the increase in allergies include an increase in the rate of caesarean sections, increased antibiotic use, increased anti-acid use, increased exposure to irritants and pollution in the air, and the delayed introduction of allergenic foods.”
Rural populations have marked protection against food allergy compared to city dwellers said Levin, likely because of the differences in gut and dust microbes in these areas.
Stellenbosch University professor of microbiology Thulani Makhalanyane said the microbiome plays a critical role in the immune system. “Evidence from recent studies suggest there may be a direct relationship between the microbiota and allergy,” he said.
“The microbiome varies considerably in children and is influenced by several factors including diet, use of antibiotics, etc.”
Makhalanyane said, however, that most studies were done in the Global North. Now his team is initiating studies on Africans in urban and rural locations “linked to the microbiome and allergy, and more specifically, acne”.
Most studies showed balanced diets rich in fibre and fermented foods promoted a healthier gut microbiome said Makhalanyane.
Paediatric dietitian Katherine Megaw said, “It all starts with their diet and gut health,” listing steps such as the early introduction of allergens, “a wide range of foods early and often”, and only using antibiotics when truly necessary. Natural birth and breastfeeding benefit the gut microbiome, she said.
Certain allergic conditions like eczema affecting the skin and asthma, affecting the airway, must be effectively and rapidly controlled, the experts urged. “Asthma itself is a risk factor for more severe allergic reactions, so should be well controlled,” Gray said, adding there was a tendency to underestimate eczema.
To correctly diagnose food allergies, targeted testing is vital, she said. “Food allergies are often incorrectly diagnosed and even over-diagnosed, but if missed, can lead to life-threatening reactions.”
She said the body can be tricked into accepting allergens over time and become less reactive through a process of desensitisation when given “tiny regular and increasing amounts of the allergen under supervision”.
Jami Darkoh's daughter, four, and son, seven, are undergoing exposure therapy with Gray related to their peanut, cashew and pistachio allergies.
“It is anxiety producing to start the exposure therapy, but they are closely monitored during the process so it feels like it is not taking an undue risk. (Our son) has gone from not being able to have any exposure at all to the nut to eating an actual nut,” she said.
“The uncertainty of whether he would be able to tolerate the exposure therapy process is better than the certainty that he will continue to have a lifelong allergy..”
But what is significant, as the latest peanut study shows, is that parents can also influence potential allergies from early on.
Dr Jeanne Marrazzo, director of the US National Institute of Allergy and Infectious Diseases, said: “The safe, simple strategy (of feeding peanut products to young children beginning in infancy) could prevent tens of thousands of cases of peanut allergy ... in the US each year.”
• Children with potentially life-threatening allergies need education on emergency management which could include an Epipen. Parents can join Allergy Foundation SA groups for support: https://www.allergyfoundation.co.za/support-groups/
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