Nearly one-third of U.S. adults and more than one-quarter of U.S. children report suffering from respiratory allergies, eczema, or food allergies. However, up to 35% of people self-diagnose a food allergy or food intolerance and self-manage their condition rather than seek clinical diagnosis from a healthcare professional. Individuals who self-diagnose may take actions such as adopting a restrictive diet that may lead to avoidable nutritional gaps, spending money on ineffective supplements, or taking antihistamines unnecessarily while the underlying cause of their symptoms remains unresolved.
While allergy self-diagnosis or misdiagnosis can have a negative or detrimental impact on a patient's allergy care, failure to test for all suspected allergens can also result in allergies going undetected, resulting in avoidable symptoms and worsening of a patient's quality of life. Undiagnosed allergies also put patients at risk for unexpected reactions, repeated emergency room visits, heightened anxiety about uncertainty, and unnecessary treatment for presumed allergies.
In addition to personal risk, underdiagnosis places a higher economic burden of allergy on the health care system, potentially resulting in billions of dollars in wasted health care spending each year. By understanding the root cause of a patient's allergies through a detailed history of symptoms and medical history, informed comprehensive allergy testing can help uncover hidden allergies, ensure effective care and smarter use of resources, and improve patient safety.
How clinicians can accurately confirm suspected allergies
Skin prick testing and specific IgE (sIgE) blood testing are two validated tests commonly used by healthcare providers that do not necessarily indicate clinical allergy, but rather sensitivity to the allergen. With an sIgE blood test, a person who develops an increase in sIgE antibodies that recognize a specific allergen is described as being sensitive to that allergen, and an increase in sIgE is associated with an increased likelihood of developing an allergic reaction when exposed to that allergen. However, sensitization does not guarantee that a person will develop an allergic reaction. In the case of food allergies, this also does not mean that a certain food should be eliminated from the patient's diet, especially if the patient is currently consuming the allergen without any problems.
Additionally, not everyone who is allergic to one food will be allergic to the same ingredients in that food. For example, patients with peanut allergies may be sensitive to different proteins. By identifying specific proteins or allergen components that patients are sensitive to, clinicians may be able to predict how they will express their specific symptoms, providing more precise guidance for patients in managing their allergies. This is especially important in helping patients understand when they may be experiencing less severe symptoms, such as an itchy mouth, versus a more systemic or even allergic reaction, or if the patient may have ingested a cooked allergen.
Because of this variability, obtaining the patient's clinical history is the most important step in the diagnostic process. A thorough patient history should assess for symptoms consistent with IgE-mediated allergy, which may affect the skin, gastrointestinal tract, cardiovascular system, and/or respiratory tract. These reactions usually occur within minutes to hours after exposure to the allergen, with the exception of certain delayed reactions, such as those observed in alpha-Gal syndrome, a mammalian meat allergy. Clinicians should evaluate the timing, frequency, and potential triggers of symptoms, taking into account factors such as work, family, and dietary habits to help identify possible allergies. Responses should also be consistently reproducible under similar conditions to support accurate diagnosis.
Understanding the underlying causes of a patient's allergy symptoms helps clinicians provide patients with appropriate treatment, whether medication, lifestyle changes or allergen-specific immunotherapy, to improve their health outcomes and overall well-being.
The negative impact of underdiagnosis on patients and the healthcare system
Underdiagnosis or delayed diagnosis of suspected food allergy not only has deleterious effects on patients but also has a negative impact on the healthcare system. For patients, the economic impact of acute reactions and anaphylaxis is considerable.
A seven-year retrospective analysis of insurance claims from 355,520 people with food allergy found that 17% of them had an emergency room visit and 0.9% were hospitalized due to their food allergy. The study also estimated that the average annual out-of-pocket cost for a food allergy visit was $1,631, or about 11 percent of the total annual outpatient, emergency room and hospital service costs of $14,395 per patient. After hospital visits, an analysis found that most patients who presented to emergency rooms with acute anaphylaxis or anaphylaxis were not given a prescription for an epinephrine auto-injector, education about allergen avoidance, or a recommendation to consult an allergist.
From a healthcare resource utilization perspective, allergic conditions such as hay fever, eczema, food allergies, and allergic asthma are common but often underdiagnosed and undertreated, placing a heavy burden on the healthcare system and leading to avoidable health complications. Systemic health care inequalities also exacerbate the effects of underdiagnosis. One study found that the prevalence of food allergies among U.S. children enrolled in Medicaid is much lower (0.6%) than previous national estimates using parent surveys (7.6%) and physician-confirmed reports of food allergy (4.7%), suggesting widespread underdiagnosis in this patient population.
Overall, food allergies are a major driver of health care costs, with one study estimating that childhood food allergies cost the United States $24.8 billion annually, primarily due to inpatient, outpatient and emergency room visits, demonstrating the importance of early and accurate diagnosis.
Why the right diagnosis is important
Obtaining an accurate food allergy diagnosis can increase dietary diversity and potentially improve nutrition after suspected allergies are ruled out, so it is crucial to have the correct diagnostic approach from the outset. Greater diagnostic specificity also allows clinicians to reduce the number of high-risk oral food challenges while performing more low-risk challenges, helping more patients receive an accurate diagnosis.
By using the right diagnostic methods and ensuring patients have an accurate, thorough understanding of their allergies, disease management can shift from reactive to proactive, thereby providing better care, reducing unnecessary resource utilization, and improving patients' quality of life.
Photo: HASLOO, Getty Images
Gary Falcetano, PA, is the U.S. Scientific Affairs Manager for Immunodiagnostic Allergy at Thermo Fisher Scientific. A licensed physician assistant with over 25 years of experience in emergency and disaster medicine, primary care, and allergy and immunology.
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