A new study offers hope to adults who live in fear of their allergic reactions, as adults with severe peanut allergies could become tolerant in a matter of weeks.
Scientists gradually introduced 21 severely allergic adults to peanut products and peanuts in increasing amounts.
By the end of the trial, 14 of them were able to tolerate a whole handful of peanuts without an allergic reaction.
Gradual exposure to allergens – otherwise known as oral immunotherapy – has been successful in previous trials on children and babies, but this is the first time it has been tested on adults.
Chief Investigator Prof Stephen Till, an adult allergy expert at King’s College London, said in a statement that his team was “very pleased with the results.”
“Constant fear of life-threatening reactions places a huge burden on people with peanut allergy,” he said. “The only way to manage a peanut allergy is strict avoidance and treatment of allergic reactions, including with adrenaline.”
Peanut allergies affect approximately 2 per cent of the general population of Western countries, according to a 2021 study, and it seems to be becoming more common.
Till said that this trial provided “preliminary evidence” that adults with severe allergies could be desensitised, and that this would improve their quality of life.
The participants in this study were 18- to 40-year-olds who had been diagnosed with severe peanut allergy at Guy’s and St Thomas’ NHS Foundation Trust.
They started out by trying tiny amounts of peanut flour mixed with food under strict supervision. The first dose was 0.8 mg – equivalent to less than 0.3 per cent of a whole peanut.
If that was well tolerated, participants would try 1.5 mg half an hour later. If that went well, they would try 3 mg half an hour after that: 1 per cent of a peanut.
Participants who were able to eat either 1.5 or 3 mg continued to eat that amount every day for two weeks. After that, they returned to the clinic and were supervised while trying higher doses.
Every day, the participants would take their dose of peanut flour. Every two weeks, it would be increased slightly – until they were able to tolerate 50 mg to 1 g of peanut protein: the equivalent of two to four whole peanuts.
When they reached that level, the participants switched to real peanuts, peanut butter or peanut products.
Chris, 28, who took part in the study, said: “All of my life, I had associated the taste and smell of peanuts with fear and death. I started with a small amount of peanut flour with yoghurt, and by the end of the trial, I could eat four peanuts in one sitting.”
Chris now eats four peanuts every day with breakfast to maintain his immunity. He added: “Before, a tiny mistake could have life-threatening impacts, but now I don’t have the fear that I might collapse and die from eating a takeaway.”
Prof Adam Fox, chair of the National Allergy Study Group and professor of paediatric allergy at King’s College London, said that, while small, this study was an “important proof of principle” that exposure may help treat allergies in adults. Fox was not involved in the study.
However, he warned: “This treatment requires careful medical supervision and should never be attempted without this.”
The study was published in the scientific journal Allergy.
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