Almost 1 in 3 U.S. adults and more than 1 in 4 U.S. children reported having a seasonal allergy, eczema, or food allergy in 2021. That’s more than 100 million people and rates are rising. While many people experience relatively mild symptoms, for others, living with an allergy can be debilitating, with symptoms being severe and, in the worst cases, even fatal.
Therefore, it is essential to ensure patients have the most appropriate treatment plans and management strategies. An accurate diagnosis is the first step in optimizing patient care, and with a chronic shortage of board-certified allergists, primary care providers (PCPs) serve as the first line of defense for patients suffering.
As pressure mounts on PCPs to bridge the gap between increasing patient demand and diminishing board-certified allergist availability, the advantages of introducing allergen component testing into clinical pathways are becoming more apparent.
The limitations of existing practice
Clinicians can order general allergy testing in the form of a whole allergen-specific IgE blood test. Using a patient’s blood sample, the test measures the level of specific IgE antibodies in response to whole allergens, such as peanuts or dog dander. This helps build an understanding of a patient’s sensitizations but, alone, doesn’t provide the most comprehensive picture.
For example, whole allergen-specific IgE testing does not allow PCPs to gain insights around potential disease severity risks, the role that cross-reactivity may play in sensitizations with homologous proteins in other allergen sources, or help predict the future development of allergic disease in children. As a result, when using whole allergen-specific IgE testing on its own, PCPs will typically need to refer more patients than is strictly necessary to board-certified allergists for further testing or oral food challenge (OFC). Given the shortage of allergists, this can result in patients who don’t need to be referred unnecessarily experiencing significant waiting times and additional travel burdens. At the same time, patients who do need specialist care are forced to wait longer due to prolonged waiting lists in part caused by unnecessary referrals.
Instead, if PCPs use allergen component testing alongside whole allergen-specific IgE testing, they will be able to manage more patients’ treatment pathways independently and make better-informed specialist referrals when needed. But what is allergen component testing?
Whole allergen-specific IgE testing tests all the proteins within the allergen, including relevant ones and those that are not. In contrast, allergen component testing tests specific proteins to which a person is sensitized. This can better target which allergens may truly cause an allergic reaction in patients. In the same way that PCPs utilize a lipid profile to understand a patient’s total cholesterol and target intervention more effectively, the same is true for allergen component testing and suspected allergies. In other words, by combining whole allergen-specific IgE testing and allergen component testing, PCPs can first determine whether there is an allergy or not and, if the former, help to identify more precisely the allergens responsible for the symptoms. This approach can revolutionize allergy diagnosis and management for PCPs, potentially improving patient care and health outcomes.
Understanding the benefits of allergen component testing
Incorporating component testing can support PCPs to predict the tolerance of different forms of food allergens that a patient is sensitized to. For example, general tests like whole allergen and skin prick tests may reveal sensitization to eggs and dairy, but allergen component testing can reveal if the cause may be limited to fresh forms of these foods only or if cooked forms, such as baked eggs and dairy, may be safe. With more in-depth data, PCPs can offer improved dietary advice. In turn, patients benefit from an enhanced understanding of their specific triggers and can enjoy a wider range of foods and a better quality of life.
Similarly, by analyzing specific allergen components, PCPs may be able to identify patients who are at higher risk of experiencing severe allergic reactions following exposure to peanuts and tree nuts early in their care pathway. This can help reduce the risk of severe reactions by informing appropriate treatment and avoidance strategies. It can also support more comprehensive referrals to specialists, where OFC testing may be an appropriate next step to rule out clinical allergy and provide a more accurate diagnosis.
Guiding pet selection is another benefit PCPs can pass on to patients. Different pets produce varying levels of allergenic proteins, and the specific allergen components can differ among species and genders. By identifying the specific pet allergen components that an individual is sensitized to, PCPs can guide patients in selecting pets that are less likely to trigger reactions. For instance, whereas whole allergen testing may confirm sensitization to the whole allergen, research tells us that up to 58 percent of dog-allergic patients only react to Can f 5 proteins, produced in the prostate of male dogs. This suggests many patients sensitized only to Can f 5 could tolerate exposure to female dogs.
Interestingly, there is also a correlation between the number of pet allergen components a person is sensitized to and the severity of the disease they are likely to express. By introducing allergen component testing, PCPs can better predict the development and severity of respiratory disease. This is particularly useful for pediatric patients, with research indicating that the more pet allergen components a child is sensitized to at age 4, the more likely they are to demonstrate a clinical respiratory disease, such as rhinitis, rhinoconjunctivitis or asthma, at age 16.
Component testing, therefore, supports early intervention, improved management strategies, and better-informed specialist referrals. This last point warrants further exploration, as a more precise understanding of allergen components can help PCPs determine if it is in the patient’s best interests to be referred to a specialist. This targeted approach ensures the right patients receive the right care from the right clinician, leading to improved patient outcomes while limiting unnecessary referrals and promoting health care efficiencies.
Take allergy diagnosis into your own hands.
Shortages of board-certified allergists, coupled with increasing allergy prevalence, are mounting pressure on PCPs to bridge the gap and better support patients. While many PCPs have already taken the first step towards this by utilizing whole allergen testing, incorporating allergen component testing has added benefits.
Allergen component testing — when used in conjunction with whole allergen-specific IgE testing and alongside clinical history — can identify sensitization to a host of allergen components, supporting more accurate and timely diagnosis. Armed with enhanced knowledge, PCPs can better predict tolerance to different forms of foods, identify patients who may be at higher risk of allergic reactions, guide pet selection, and help predict disease. With a diagnosis at the heart of the clinical pathway, allergy patients can be effectively qualified for specialist referrals, treatment plans, and management strategies can be better targeted, and patient care can be improved to maximize the quality of life for allergy patients.
Niti Chokshi is an allergy-immunology physician and Gary Falcetano is a health care executive.
