The RAST test is scored on a scale from 0 to 6:
| RAST rating | IgE level (KU/L) | comment |
|---|---|---|
| 0 | < 0.35 | ABSENT OR UNDETECTABLE ALLERGEN SPECIFIC IgE |
| 1 | 0.35 - 0.69 | LOW LEVEL OF ALLERGEN SPECIFIC IgE |
| 2 | 0.70 - 3.49 | MODERATE LEVEL OF ALLERGEN SPECIFIC IgE |
| 3 | 3.50 - 17.49 | HIGH LEVEL OF ALLERGEN SPECIFIC IgE |
| 4 | 17.50 - 49.99 | VERY HIGH LEVEL OF ALLERGEN SPECIFIC IgE |
| 5 | 50.0 - 100.00 | VERY HIGH LEVEL OF ALLERGEN SPECIFIC IgE |
| 6 | > 100.00 | EXTREMELY HIGH LEVEL OF ALLERGEN SPECIFIC IgE |
Shellfish (crab, shrimp, etc): her rating 3 - the Doctor advised us to keep them away from her but he felt good about her growing out of this allergy!!!!!!!!!!!!!!!!!!!!!!!! YAY!
Egg (mostly egg whites): her rating low 4 - our doctor advised us to continue to stay far away from eggs but he hopes that she will in the not near future that she will out grow this allergy.
Tree nuts- her rating was 4 - He said that Charlotte should avoid them but could more than likely out grow some of them due to the range
Peanuts(this is a dirty word in our house and will continue to) - her rating 5/6 GRRRRRRRRRR! Our doctor said that this is extremely severe and to avoid them at all costs. He said there is a 5% chance she will outgrow this in her life time. When we had her tested in June she was a 77out of 100 and now she is a 93 out of 100! It has gotten worst in just 6 months :(
Now I have to remind myself that this is a baseline and that it could change. I hope that it changes. I pray that it changes. But for right now we are educating ourselves on everything there is to know about tree nuts and peanuts. I started reading the book "The Peanut Allergy Answer Book" to fully understand it and know how to approach it with Charlotte in the future.
This is why we are soo cautious with Charlotte. We do not take her out to eat for fear of cross contamination to nuts and tree nuts. We have found many new fun recipes that do not contain peanuts or tree nuts that we all can enjoy and that she loves! It is tricky but it will soon just become natural.
I bought doughnuts the other day and I had to call around to all the places to see if they use peanut oil and if there is any cross contamination and out of the four places I called only one knew that they didn't use peanut oil and that they did not cross contaminate. The other places didn't know what type of oil they used and had to call me back! AHHH! A lot of restaurants do not know what they are using unless I ask the manager. So for now we just do not go out to eat with her.
We made cookies over the holidays and found out the the red dye for making icing was made in the same facility as peanuts. THEY ARE EVERYWHERE. We have gotten really good at reading labels.
The doctor also recommends that we have George tested before he starts solid foods so that will be a blog post next month. PLEASE KEEP YOUR FINGERS CROSSED that he is not allergic to nuts also!
Here are some common questions about peanut allergies.
Common Questions and answers
Outgrowing Peanut Allergy
- Can my child outgrow his allergy even if he has had an anaphylactic reaction in the past?
In one study, the children who successfully outgrew their peanut allergy had fewer reactions, less anaphylaxis and fewer allergies. However, in other studies, there were children with a history of anaphylaxis who did successfully outgrow their peanut allergy.
- Can my child outgrow even if his peanut score is over 100?
For a child with a score of over 100 to outgrow the allergy, the score must decline over time. This happens, even with a very high score.
I would recommend repeating the RAST test over a period of several years to see if any decline does occur. If it does not, the allergy is not likely to resolve.
- When should I consider an in-office food challenge for my child?
I would be confident of this if the patient had a negative skin test and low to negative RAST test.
I would consider a hospital challenge if I considered the likelihood of passing greater than 50%. This is a decision your allergist will make, based on clinical history of reactions, and test results over time.
Airborne Reactions
- Is air travel dangerous?
I recommend booking the first flight of the day, when the airplane is at its cleanest, without contamination of foods and passengers that increases over the course of a busy day. If your child is young, pre-board so you have time to inspect the seats and tray tables and perhaps clean if necessary. Generally, airlines want your business and are usually very accommodating to travelers with medical and special needs. You just need to prepare well ahead of time to ensure a safe flight.
- My son has had a reaction to peanut in the past. How do I know if he is at risk of an airborne reaction?
Typically, airborne exposure occurs in the setting of cooking/heating causing vaporization, recycled air of aircraft cabin with peanut dust from vacuum packed snacks, hi density consumption of peanuts in public venues such as sports arenas, circuses, etc. Allergic symptoms from this type of airborne exposure are typically itchy eyes, sneezing, runny nose, cough, similar to the allergy symptoms triggered by pollen or animal danders.
Anaphylaxis is uncommon in this setting unless ingestion or systemic absorption occurs. A recent carefully performed scientific study showed that the smell of peanut butter does not cause anaphylaxis.
- Does a high or low score to peanut mean that my child will or wont have an airborne reactions?
Severity and Reactions
- Is there such thing as a "mild" peanut allergy?
- Are children who have had "only" hives in reaction to peanut at risk of anaphylaxis in the future?
- Should a child with history of a mild allergic reaction to peanut carry epinephrine-even if the reaction was "only" hives?
For someone who has never had a reaction, there would be no basis for classification. However, reactions are often very unpredictable and may vary from exposure to exposure; there is not necessarily a pattern that is followed. Reactions do not necessarily worsen with each new exposure. They can be mild one time and severe the next time.
A patient who has only had a past history of "mild reactions" is equally at risk for anaphylaxis with future exposures. That is the reason why I prescribe all patients with food allergy epinephrine autoinjectors regardless of history, because of the potential for anaphylaxis.
