Dr. Hemant Sharma is the Associate Chief of the Division of Allergy and Immunology at Children’s National Medical Center in Washington, D.C.  He is also the Director of the Food Allergy Program and site director for the National Institutes of Health Allergy and Immunology fellowship program.  Dr. Sharma obtained his medical degree from Columbia University, and completed his pediatric residency and chief residency at Duke University.  He trained in allergy and immunology at Johns Hopkins, where he also completed a degree in clinical epidemiology.  He is a regular contributor to a food allergy column in Allergic Living magazine and recently co-edited the “Food Allergy in Children” series for Pediatric Clinics of North America.

Dr. Sharma, thank you for helping us to learn more about asthma and food allergies. Dr. Ruchi Gupta’s recent research found that nearly 8% of US children under 18 have food allergies. Do you know of recent research that has determined how many children with food allergies also have asthma? In your practice, how many children have both?

Food allergies and asthma often do occur together.  Prior studies suggest that more than a third of children with food allergies also have asthma, and up to 8% of asthmatic children have a food allergy.  It is not uncommon for us to see something called the “atopic (or allergic) march” in children, where they start out in infancy with food allergy and then go on to develop asthma and hay fever later in childhood.

My son had Respiratory Syncytial Virus (RSV) at 3 weeks old. We heard that this would make him more likely to have asthma. Is this true? Is there any relationship between RSV and food allergies?

RSV infection in infancy has been shown to be associated with a higher chance of developing asthma later in childhood.  Interestingly, wheezing with rhinovirus (the common cold virus) in early childhood is actually a much stronger risk factor for later asthma than RSV.  It’s not entirely clear if these viruses cause asthma or are simply predictors of childhood asthma.  There is not any evidence for a connection between RSV and food allergy.

Is asthma the same as “reactive airways”? Is it medicated the same?

The term “reactive airways” is often used by health care providers to describe wheezing in early childhood, when it may not yet be certain whether that wheezing will resolve over time or develop into chronic asthma.  One of the hallmarks of asthma is reactivity or “hyper responsiveness” to triggers, which can lead to tightening around the airways during a flare-up.   Both “reactive airways” and asthma may be treated with the same medications, for example bronchodilators like albuterol, which help relieve this tightening around the airways.

Is there a different protocol for your patients who have just food allergies versus those who have both food allergies and asthma? How about children who have the atopic trifecta: food allergies, asthma and eczema?

The management of food allergies is similar whether a child has food allergies alone, or accompanying asthma and/or eczema.  Food allergen triggers should be avoided, and in some cases, this may help to improve eczema control as well.  In addition, emergency medications to treat food-allergic reactions should be available at all times, including epinephrine, antihistamine, and, if a child has asthma, albuterol.  For children who have both food allergy and asthma, asthma symptoms might certainly be part of a food-allergic reaction, but they are usually not the only symptom observed.

My son has severe peanut & tree nut allergy – among several other foods – and mild asthma. I’ve read that two of the risk factors for fatal anaphylaxis are peanut or tree nut allergy and asthma. (The third being a delay in the administration of epinephrine). Why are peanut/nut allergy and asthma implicated with this higher risk of a fatality? What should my son be doing to mitigate this risk?

Certain foods, like peanuts and tree nuts, have been shown to be associated with a higher risk of fatal reactions.  The reasons are not entirely understood, but likely are related to unique biochemical properties of these allergens.  It is also important to note that fatal reactions have occurred to many foods other than nuts.  Asthma is another risk factor for fatal food allergy reactions.  This might be explained by delayed use of epinephrine since people with asthma might often reach first for their inhaler when they are experiencing breathing difficulty, and overlook other signs of anaphylaxis.  For patients with both food allergy and asthma who develop abrupt respiratory symptoms, it’s advised they assess whether other symptoms of anaphylaxis are being experienced, and if so treat immediately with epinephrine.

For years we thought that my son had outgrown his asthma. When we went to National Jewish Hospital a year ago, he had a Nitric Oxide test that our local allergist wasn’t able to administer in her office. We then found out he had likely had mild asthma all along and had gotten accustomed to a tight feeling in his chest. Our allergist’s testing methods weren’t refined enough to pick up the problem, and my son didn’t know he was having difficulties. Should we parents be looking for certain signs of asthma if our children have other allergy issues?

The most commonly used test to evaluate lung function in asthma is spirometry.  This form of lung function testing measures obstruction to air flow, usually before and after receiving a bronchodilator medicine, like albuterol.  Nitric oxide testing, instead of measuring obstruction, detects airway inflammation, which might be present in uncontrolled asthma.  While this test may provide useful information in some cases, it cannot by itself diagnose asthma, and is not a test that needs to be done for every child with asthma.  In fact, studies have not shown that using nitric oxide testing helps to improve asthma control, beyond relying on a thorough assessment of symptom frequency, need for albuterol and spirometry results.

There is more research recently to find a cure for food allergies. I’ve read that asthma kills 9 persons a day sadly, in the USA alone. What research is there to find a cure for asthma? Do you see any great new asthma medications on the horizon?

Research is also under way to identify new treatments for asthma.  Omalizumab (Xolair) is an example of a new asthma medication that has helped patients with severe allergic asthma, who failed to respond to other asthma treatments.  It functions by blocking the binding of the IgE antibody.  This medication is also being studied for potential use in food allergy.

Thank you Dr. Sharma!