Pearls from the annual meeting of the American Academy of Allergy, Asthma, and Immunology

Saints celebrate a Super Bowl win

I just returned from New Orleans where I attended the American Academy of Allergy, Asthma, and Immunology (AAAAI) annual meeting. It was very hard for an Indianapolis Colts fan to venture into the city that beat my team in the most recent Super Bowl. They still celebrate that victory – deservedly so. It’s just that everywhere you go you see ‘Who dat’ Saints stuff. 

At this meeting I had two major agendas; to update my understanding of the conditions I see and care for in my profession and to begin the process of recruiting our third full-time allergist for Riley Hospital. When I got to Riley in 1994, I was the first staff allergist there in 22 years. The allergy service has been up and running. We (Dr. Vitalpur and I) are looking to expand and we need to expand.  We interviewed a few current fellows in training and we look forward to their visits with us. It is exciting to interact with physicians currently in their training programs. These are young people eager and ready to embark on their career choice of patient care, teaching, and research in the field of allergy/clinical immunology. This is an exciting time for the allergy program at Riley. 

In a later posting I plan to include more material on food allergy. I have been invited to give an update from the meeting (food allergy topics only) at a food allergy support group this Tuesday (March 16) in Greenwood, In.  My thought is to have the group hear my presentation first then publish it on the web. The early preview of the update is for the support group. 

Food Allergy 

More on this later however, the meeting had many talks on the concept of ‘tolerance’. The is the condition by which despite a specific IgE (blood test/skin test) to a food that food has been ingested and continues to be ingested without any clinical symptoms. 

Now here is the clinical scenario that we need to think carefully about. Trail mix (made of peanut and tree nuts and other stuff) is ingested and an allergic reaction occurs. The child is treated in the office and the advice is to not eat peanuts or tree nuts. Blood is drawn and the specific IgE is positive to a number of tree nuts and to peanut. The history of food exposure before the reaction indicated that roasted peanut products are eaten every day by this child. Tree nut exposure has occurred in the past but very irregularly. So which food caused the reaction? Peanut which was a daily part of the child’s diet (you have exposure, constant ingestion, and an positive allergy test) or a tree nut (you have exposure, rare re-exposure, and a positive allergy test).  In this case, despite a positive IgE to peanut, the child was ‘tolerant’ to peanut. The history indicated that there was frequent exposure to peanut. The problem is that by avoiding peanut, tolerance may be lost and re-introduction of peanut may cause clinical symptoms. 

Food sensitization in children may be due to environmental exposures to the food (vs. ingestion). 

The Future of Inhalant Immunotherapy 

Currently we have subcutaneous (SQ) allergen immunotherapy (IT)- allergy shots, injections. This form of therapy has been well established for 100 years. It is somewhat crude/unrefined and reactions can occur. The advances in this field include; 

1.  Sublingual immunotherapy (SLIT)- not approved in this country 

2.  Peptide immunotherapy (PIT) 

3.  Allergen fusion proteins 

4.  Allergens attached to viruses 

Anaphylaxis 

Fatal allergic reactions may not always have skin manifestations. Low blood pressure was seen in 80% and 60% had respiratory effects. Skin reactions occurred in 60%. All too often there is a delay in recognizing anaphylaxis when skin reactions are absent. Not everyone experiencing an anaphylactic reaction will have a skin reaction. 

Asthma 

I was involved as a principle investigator in the first phase of the National Cooperative Inner-City Asthma Study (NCICAS). I attended a session on inner-city asthma given by Herman Mitchell. Dr. Mitchell has been involved with this issue for many years. He shared a number of observations that spanned almost two decades of investigation. 

            Asthma is not just one disease. It is many diseases. It is complex and multi-causal. There are many factors that interact that determine its development and its exacerbations. This would be true for all populations with asthma. 

            The inner-city asthma studies emphasized the importance of sensitization (having a positive allergy test) and exposure (measuring the allergen in the environment). 

            House dust mites were found more often and in greater amounts in detached, low-rise housing and less in high rise apartments. In evaluating a child with asthma, we need to know what type of building they live in. 

            High humidity in the home is a factor. 

            Air pollution poses a conundrum. Overall air pollution levels have decreased, yet asthma prevalence has increased. Could this be a protective effect? Approximately 25% of children currently live in environments that exceed the standards for safe air. Things to consider in the child’s environment include how far away they live from a main road. 

            Asthma is a weighty problem. Inner-city asthma studies have shown 29% of the children with asthma are obese and 56% are over the 85%tile for weight. Between 85-90% of the child’s time is spent indoors where it would be difficult for active play/exercise. Safety concerns of the inner-city environment contributes to this problem. 

Human Genome Studies 

            This is a very hot topic. Most of it is research based however one of the anticipated outcomes would be to look at someone’s genetic profile and be able to predict susceptibility, expression, and severity of asthma and allergic diseases. We may be able to predict the kind of asthma someone will have and design very specific programs to prevent/treat. 

Asthma Treatment- Inhaled Corticosteroids 

            Not everyone responds to inhaled corticosteroids (ICS) given for asthma. Up to 50% of those on ICS may not respond. There are no biomarkers that we can use to determine in which patients a ICS will work; we depend on a clinical response. 

            The question is how long do you wait until it is determined that the ICS has made no difference? 

            This presentation posed many probing asthma management questions. It is important to set goals/outcomes when starting a program and to bring the patient back in a reasonable period of time to see if those goals/outcomes have been achieved. We also have to make sure that there was adherence to the therapeutic program (it is hard to tell if something was a failure/success if it was not used). In this situations it may be of benefit to start at a higher than anticipated dose looking for any response. 

Allergy Blood Testing 

            There are three companies that offer the blood tests for IgE and the results they provide are not equal. You cannot compare one with the other. 

            The future microarray technology will help us sort out relevant allergens. Skin testing and blood tests for allergy use very crude protein extracts that may have different and numerous proteins. The results obtained may be due to cross-reactivity with other substances or even binding to proteins that cause no clinical reactivity. 

            Of importance- the blood test result, the concentration of IgE antibody (kU/L) provides predictive power for a reaction it does not tell us anything about the severity of a reaction. 

            Do not use the term RAST- it is outdated, it refers to a technology no longer used. 

Urticaria- Hives 

            This is one of the most frustrating clinical conditions that we see. Parents, patients, and healthcare providers want the answer for the hives. I think the frustration of not knowing will continue. Idiopathic is the medical term used to describe something for which no cause has been determined. In some contexts it means the healthcare provider is the ‘idiot’ because they were unable to figure it out. 

            More than 80% of the time, chronic (more than 2 months) hives is idiopathic. The evaluation needs to consider the role of aspirin and other non-steroidal anti-inflammatory medications. Physical reasons for hives also need to be considered (light, pressure, water, heat, cold, or vibration). 

            The list of agents used to treat hives was described as ‘weird’. Frequently, a typical (H1) antihistamine has added to it an H2 antihistamine (commonly used to treat excess stomach acid). There are a variety of combinations used, however the definitive study that showed a positive effect was the used of hydroxyzine and cimetidine. The mechanism of action was the impact of the cimetidine on the liver metabolism of the hydroxyzine- cimetidine allowed the hydroxyzine to be around longer. 

            A somewhat new therapy for hives was the immunosuppressive agent cyclosporine. Adding a second H1 antihistamine may help. 

These are some of the highlights from the meeting. More specifically these comments come from the notes taken that I could read. 

Check-in next week – I plan to post my notes on the majority of food allergy topics after my presentation on March 16, 2010. 

FEL 

March 11, 2010 · fleickly · No Comments
Tags:  · Posted in: AAAAI Meeting Higlights, Allergies, Asthma