Family history plays a large role in diagnosing allergies.
Many chronic medical conditions may stem from underlying allergic process: rhinitis, asthma, bronchitis, sinusitis, atopic dermatitis, otitis, conjunctivitis, headache, GI problems and, of course, drug allergies and anaphylaxis. Your physical exam— along with allergy testing — can often help make a specific diagnosis. However the diagnosis begins before you get there. The History is always a key element in the diagnostic process. I have found that, in regards to allergy, the Family History may be the most important component of all.
Allergic diseases have a clear genetic link. While the exact transmission of allergies has not been precisely defined, medical research has demonstrated a strong familial relationship. Allergic parents tend to have allergic children. It makes sense that allergic asthma follows the same pattern. In fact the greatest predictor of childhood asthma is not IgE levels or any other specific allergy skin or blood test; it’s maternal asthma.
IgE-mediated allergic disease can manifest with a variety of presentations. I always ask my patients if anyone in their immediate family — parents, sisters, brothers, aunts, uncles, grandparents, and don’t forget the patient’s own children — has allergies. You sometimes have to give them a nudge by specifically mentioning sinus disease, skin rashes, asthma or allergy to Penicillin. Each of these are indicators of IgE-mediated disease in the family.
I have found the link to be so strong, in fact, that when a patient presents to me with asthma and no family history of allergy, I have doubts. If they had no immediate relatives with allergy, I perform an extra careful search for a non-allergic source for their respiratory symptoms. Of course, I still investigate the allergy angle for the sake of completeness and the possibility that their family members have not been properly diagnosed. But if the family history is truly allergy-free, there is generally another source for the patient’s symptoms, such as Alpha 1 antitrypsin deficiency — an enzyme deficiency that can mimic asthma and bronchitis.
Patients often ask, “My mother (or father) has a specific food or drug allergy, do I need to avoid that product?” The patient has no symptoms but the parent has a terrible reaction to a food or medicine. This is tricky. My advice is to be vigilant! We are not identical replicas of either of our parents but it is wise to be on the alert for any symptoms of allergy to parents’ severe triggers and to avoid the offender at the first hint of a symptom. This recommendation is consistent with my frequently-lectured theme to medical students and patients alike: allergic sensitization occurs after repeated exposure. Sometimes it takes several exposures before the body’s IgE response erupts in a clinical reaction.
We can’t escape our genetics, but we can limit or avoid potential allergen exposures. This holiday season of Christmas, Hanukah and Kwanzaa, when surrounded by family, it might be a good idea to ask around and complete your own Allergy Family History!
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