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- Over 4.6 million U.S. adults live with peanut allergies. This number is going up because of cases that start in adulthood.
- A major study found that 32% of adults could handle 5 peanuts after 2.5 years of oral immunotherapy.
- OIT changes how the immune system acts, affecting IgE levels and T-cell function, even in adult immune systems.
- Peanut allergies can hurt mental health, causing more worry and making life feel less good.
- Adult OIT has risks. 17 people left the study because of bad reactions. This shows why a doctor needs to watch over treatment.
Peanut Allergy in Adults: Can Daily Doses Help?
Roughly 4.6 million adults in the U.S. currently live with a peanut allergy. This condition often changes life and people used to think only children had it. But with more people getting allergies as adults, doctors are looking again at how to help with the symptoms. One promising option is oral immunotherapy (OIT). It uses small daily amounts of peanut protein to help the immune system get used to it. A new study shows that adults, too, might get help from this method. This gives hope for more freedom.
Understanding Peanut Allergy in Adults
Adult peanut allergy comes in two main kinds
- Allergies that started in childhood and stayed into adulthood, and
- Adult-onset peanut allergies, which show up even if someone ate peanuts fine before.
Doctors have studied childhood allergies a lot, but they are just starting to figure out adult cases. We don’t fully know what causes adult-onset peanut allergy, but things like these might play a part
- Changes in gut bacteria
- Things in the environment
- Stress or problems with how the immune system works
- Hormone changes or sickness that shifts immune tolerance
Symptoms in Adults
Adults with peanut allergies might have
- Hives or itchy skin
- Swelling of the lips, face, and throat
- Stomach problems like throwing up, diarrhea, or cramps
- Breathing problems like wheezing and shortness of breath
- Anaphylaxis—a sudden, dangerous body-wide reaction
What makes peanut allergy especially unsafe is that some people react badly to even tiny amounts. This can be as little as a nanogram of peanut protein. Being so careful affects social life, job choices, travel, and feeling calm day-to-day.
Peanut Allergy Is Usually Lifelong for Adults
Unlike children, where some allergies go away, food allergies that start in adulthood often last a long time. According to Gupta et al. (2019), more than 80% of adults with food allergies say they are bad enough to need emergency care or very careful avoidance.
This seriousness and lasting nature show the need for better ways to treat the allergy, not just avoiding peanuts.
What Is Oral Immunotherapy (OIT)?
Oral immunotherapy (OIT) is a doctor-managed treatment. Patients eat slowly increasing amounts of the food they are allergic to—in this case, peanut protein—over a long time. The main goal is not to “cure” the allergy but to
- Make the immune system less sensitive,
- Make allergic reactions less severe, and
- Offer protection if someone eats peanuts by accident.
The method uses daily doses. It starts with very small amounts (like 0.1 mg of peanut protein) and slowly goes up with a doctor watching. Over months or even years, this can teach the immune system to handle more peanut exposure without reacting.
How Does OIT Work?
How it works exactly is still being learned. But some main immune system changes happen during OIT, including
- Lower amounts of peanut-specific IgE antibodies,
- Higher amounts of IgG4 (“blocking antibodies”) that work against IgE,
- Changes to types of T-cells, especially regulatory T cells (Tregs) that stop too much immune reaction.
This change in the immune system is like teaching the immune system again. It signals that peanuts are not harmful in the amounts given.
The only OIT treatment approved by the FDA so far is Palforzia. It is specifically for children aged 4 to 17. Until recently, doctors didn’t know if adults—with their more set immune responses—could get help from a similar method.
Important Findings: First Study in Adults
A recent study where some people got the treatment and others got a fake treatment (double-blind, placebo-controlled trial) was published in Clinical & Experimental Allergy by Spiegel & Wainstein (2024). This study brought about a big change in thinking about adult peanut allergy.
Study Overview
- People in the study: Adults with peanut allergy, aged 18 and older.
- Treatment: Eating small amounts of peanut protein every day for 2.5 years.
- Results: After treatment, 32% of people in the OIT group could eat as much as five peanuts without showing allergic signs.
- Placebo Group: Only 2% reached this level of being able to handle peanuts.
This is the first big study with a control group testing oral immunotherapy for peanut allergy in adults. The results change the old idea that adult immune systems are too fixed to be retrained.
How OIT Changes the Adult Immune System
Doctors used to think children have more flexible immune systems that change easily with new exposures. Adults, on the other hand, were thought to have immune systems that are more “locked in.”
But this research shows that even in adult immune systems, getting small amounts over time can change how the body reacts. Some key ways this happens include
- Less action from mast cells and basophils, which cause the first allergic reaction.
- Changes to immune cells that affect how genes work without changing the genes themselves. This impacts how cells react to peanut proteins.
- More making of cytokines like IL-10 and TGF-β, which help create tolerance.
Also, newer research suggests that the brain also helps manage immune responses. Basically, getting the exposure repeatedly while feeling safe could help the brain reset its reaction to peanuts over time.
The Mental Health Side: Good Things About OIT You Might Not See
Food allergies are not just a body problem. According to DunnGalvin et al. (2019), adults with food allergies often have
- More worry and being overly careful
- Feeling cut off from others and avoiding things
- A higher chance of feeling down
- Trouble traveling or eating out, making life feel smaller
Oral immunotherapy can build a feeling of being safer in the mind. If a person knows they can handle 5 peanuts, they might feel less worried about eating at restaurants, flying, or trusting food labels. This less fear means
- More being able to do things on your own,
- Feeling better about yourself, and
- Better life quality.
Adding mental health help to treatment plans is becoming more common. It helps people stick with treatment and handle symptoms well.
Risks, Problems, and Side Effects
Even with the hope OIT offers, it is not right for everyone. In the same study
- 17 people stopped treatment because they had bad allergic reactions during it.
- Common side effects were stomach pain, itchy mouth, and skin rashes.
- In rare cases, some had anaphylaxis and needed emergency shots.
These results make it clear that OIT should never be tried without a doctor watching. It’s a method with big chances of good results, but also big chances of problems. Having a controlled way to give doses and being able to react fast are very important.
Also, doctors are still studying how to keep up the protection over time. If daily doses stop, will the body quickly become sensitive again? Early findings suggest needing ongoing, maybe once in a while, “booster doses” to stay desensitized.
Why This Study Is Important
Before this study, most adult patients were told that staying completely away from peanuts was the only real choice. This trial showed a new path.
What’s important
- Showed that adult immune responses can change
- Used a careful study setup (double-blind, placebo-controlled)
- Reached clear clinical desensitization
This doesn’t just change the old idea of staying away forever. It also opens the door for studying adult treatments for other food allergies (like tree nuts, shellfish, sesame).
Adult OIT vs. Pediatric OIT
Palforzia was approved for kids aged 4–17 based on studies that suggest children’s immune systems get used to immunotherapy more easily. But now, key differences for adults are showing up
| Feature | Children | Adults |
|---|---|---|
| Immune Flexibility | High | Medium to Low |
| Handling Doses | Generally Better | More Side Effects |
| FDA Approval | Yes (Palforzia) | None Yet |
| Clinical Trials | Happening but Solid | Just Starting to Grow |
Still, the new adult information suggests treatment plans made just for each age group might give adults better results. This could include
- Slower increases in dose
- Extra treatments (like antihistamines, steroids, biologics)
- Help with behavior and feelings
Practical Steps for Adults Thinking About OIT
If you live with a peanut allergy and are interested in this new treatment, here is what to think about
- Talk to Your Allergist: Only a certified allergist can tell if this treatment is right for you based on your health history.
- Look for Clinical Trials: Many universities and hospitals are doing adult OIT studies approved by the FDA.
- Know What It Takes: OIT lasts months to years. You need to be consistent, be monitored, and know there might be small problems along the way.
- Be Ready Mentally: The process can cause worry. Look for clinics that offer mental health help along with the treatment.
The Role of Psychoneuroimmunology
Psychoneuroimmunology (PNI) is the study of how the brain, immune system, and hormones work together. It matters a lot in caring for food allergies because
- Feeling stressed or upset can start or make immune reactions worse.
- Being worried all the time might cause swelling by messing up cortisol levels.
- Feeling good, like trusting the treatment, can help the immune system adapt better.
In OIT treatment plans, including
- Mindfulness or CBT talks
- Support groups for people with allergies
- Programs to help manage stress
can help patients stick with treatment and handle symptoms well. The next steps in OIT plans might benefit a lot from including these kinds of supports.
The Future of Peanut Allergy Treatment in Adults
Looking forward, what’s next for adult peanut allergy treatment might include
- OIT plans made for you based on tests (IgE levels, gene maps)
- Probiotics to help the gut talk to the immune system better
- Biologics like omalizumab used to lower OIT side effects
- Plans to check on patients for a long time to see if the desensitization lasts
The goal is not just being able to handle some peanuts, but maybe one day the allergy going away completely—where patients don’t need daily exposures anymore to stay safe.
What Adults Should Know Before Trying OIT
While these new findings are exciting, it is good to be careful
- Trying this treatment yourself is unsafe.
- Food allergy reactions can get worse fast.
- A doctor must watch you closely. There is no way around this.
Adults who want to try OIT should make sure
- They get allergy tests first.
- The treatment is approved by the FDA or part of a proper clinical trial.
- They learn about using antihistamines and what to do for anaphylaxis.
Expert Perspectives
Experts in the allergy field have said this research is a big step. As Dr. Hugh Sampson said
“This may be the start of a new time in adult food allergy care, though we still have much to find out about long-term protection and how different people respond.”
His caution is something many share: while the success is promising, doctors are still working on making the method better.
Final Point: Small Doses, Big Help
For a long time, adult peanut allergy was seen as something that couldn’t change, a life of daily limits. Now, oral immunotherapy is changing that idea. By using small, controlled exposures, the immune system—even in adulthood—can learn to calm down. This finding doesn’t promise to cure everyone, but it gives control, safety, and hope.
If you are one of the millions dealing with peanut allergy as an adult, talk to your doctor about supervised clinical trials and new ways to get help. A better future might be close by with the right treatment.
Citations
- Spiegel, H., & Wainstein, B. K. (2024). Oral immunotherapy in adults with peanut allergy: the first double-blinded, placebo-controlled study demonstrates significant desensitization effects following 2.5 years of treatment. Clinical & Experimental Allergy.
- Gupta, R. S., Warren, C. M., Smith, B. M., Jiang, J., Blumenstock, J. A., Davis, M. M., & Nadeau, K. C. (2019). Prevalence and severity of food allergies among US adults. JAMA Network Open, 2(1), e185630. https://doi.org/10.1001/jamanetworkopen.2018.5630
- DunnGalvin, A., Roberts, G., Austin, M., Kenna, F., & Hourihane, J. O. (2019). Psychological impact of food allergy in adults. American Journal of Clinical Nutrition, 109(5), 1180–1189. https://doi.org/10.1093/ajcn/nqy305
