Peanut allergy is a type of food allergy, a condition where the immune system overreacts to a particular protein in that food. Even if someone with peanut allergy only ingests a little of the food, the reaction can be severe.
Many food allergies are first diagnosed in young children. Peanuts are among the top eight foods that cause the majority of allergic reactions. The other seven are: cow's milk, eggs, fish, shellfish, soy, tree nuts, and wheat.
Food allergy is not the same as food intolerance. While some symptoms are similar, the difference is very important. Food allergy reactions can be life-threatening, and people with food allergies must be very careful to avoid their food triggers.
Peanut allergy is a growing health concern. Some estimates suggest between 1-3 percent of children in many westernized countries suffer from the condition.
While various methods have been used to estimate the size of the problem, it seems to have increased in the past 10-15 years, suggesting prevalence may have tripled in some countries such as the United States.
Advice and evidence on peanut allergy prevention
There was a time when the advice from health experts was that young children with an allergy to peanuts should avoid the food.
However, evidence from research is leading experts to review the advice. For instance, following last year's publication of results from a randomized controlled trial of over 600 children, experts in the U.S. have issued interim guidance on early peanut introduction and the prevention of peanut allergy in high-risk infants.
More recently, a large review of research suggests feeding peanut and eggs to infants is likely to lower their risk of developing allergies to these foods later on.
Thus, experts are cautiously coming around to the view that training the immune system to tolerate exposure to the food that produces allergic reactions is a way forward. Now researchers need to find effective ways to do this.
The new study, sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), investigates the safety and effectiveness of a wearable skin patch that delivers small amounts of peanut protein through the skin.
The 1-year results from the ongoing trial of epicutaneous immunotherapy (EPIT) reveal that the patch shows promise in treating children and young adults with peanut allergy, but it was more effective in younger children.
The results, published in the Journal of Allergy and Clinical Immunology, also found the skin patch is safe and well-tolerated, and nearly all participants used it daily, as directed.
Skin patch was more effective in younger children
The randomized clinical trial, which took place at five sites, recruited a total of 74 peanut-allergic volunteers aged 4-25 years. Participants were treated with patches containing either a high dose of peanut protein, a low dose, or a placebo.
The participants applied a new patch every day - either to their arm or between their shoulder blades.
The patches are not yet approved by the Food and Drug Administration. They have the trade name Viaskin and were provided for the trial by the biopharmaceutical company DBV Technologies.
After 1 year, the researchers assessed how well each participant was able to eat at least 10 times more peanut protein than they were able to consume before the study.
The results showed that 46 percent of participants on the low-dose patch and 48 percent on the high-dose patch were able to tolerate that amount of peanut protein, compared with only 12 percent of the placebo group.
The researchers also note that the peanut skin patches triggered immune responses similar to those seen in other types of experimental immunotherapy for food allergy.
The greatest benefit, however, was seen in the youngest participants - children from 4-11 years old. Treatment effects were significantly diminished in participants aged 12 years and over.
Some trials have used the oral route to administer the peanut protein, which the researchers note is difficult for around 10-15 percent of children and adults to tolerate. By using a skin patch, the new study overcomes this.
Another important result is the high level of adherence. Nearly all the participants followed the treatment as directed. None reported serious side effects. Most had mild skin reactions like itching or a rash at the patch site.
"The high adherence to the daily peanut patch regimen suggests that the patch is easy-to-use, convenient and safe. The results of this study support further investigation of epicutaneous immunotherapy as a novel approach for peanut allergy treatment."
Co-author Dr. Marshall Plaut, NIAID Division of Allergy, Immunology and Transplantation
The study is ongoing and will continue to assess the long-term safety and effectiveness of the peanut allergy skin patch.
The researchers also note that larger trials with larger groups of children will have to assess the treatment before it can be approved for clinical use.
Epicutaneous immunotherapy for the treatment of peanut allergy in children and young adults, Stacie M. Jones et al., Journal of Allergy and Clinical Immunology, doi:10.1016/j.jaci.2016.08.017, published online 16 August 2016, abstract.
National Institutes of Health news release, accessed 27 October 2016.
Additional source: American Academy of Allergy, Asthma & Immunology: Food Allergy, accessed 27 October 2016.
Additional source: Consensus communication on early peanut introduction and the prevention of peanut allergy in high-risk infants, David M. Fleischer et al., Journal of Allergy and Clinical Immunology, published August 2015, accessed 27 October 2016.