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Guidelines recommend that factors that trigger or exacerbate asthma must be elicited routinely and documented in the medical records and action plans of all patients with asthma.1,2 A few key questions, followed by confirmatory testing, will provide you with a detailed history and help you create an effective management plan for your patient.
History alone is often not enough to accurately identify all of the patient’s allergic triggers. For example, a patient can present with a history suggestive of house dust mite or cat allergy but actually not be sensitized.2 Likewise, a patient can present with a few non-specific symptoms, but the cat may be the primary trigger.
Allergen sensitization testing improves accuracy of results vs. patient history alone2
Guided by the allergy-focused patient history, the next step should be testing. When added to an allergy-focused patient history, the use of skin prick tests (SPT), serological tests, or both increases your confidence in diagnosis and clinical management by ruling in or ruling out allergies.3,4
|KEY ALLERGY TEST DIFFERENCES
|| Specific IgE blood testing
||Skin prick testing|
| Typically ordered and reviewed by a clinician
| Patients do not need to discontinue allergy medications
| Requires only one needle stick (a single blood sample)
| Carries no risk of severe allergic reaction
| Can be used when extensive skin rash is present
| Component testing is available
| Same day results in the office
Just as diagnostic testing is routine for diagnosis of chronic diseases such as type 2 diabetes and dyslipidemia, specific IgE tests can be routine to aid in the diagnosis of allergic disease.
As allergies trigger asthma exacerbations in up to 60-90% of children and about 50% of adults with asthma,6,7guidelines recommend factors that trigger or exacerbate asthma must be identified routinely and documented in the medical records and personal asthma action plans of all patients with asthma.1 Reducing exposure to one or more allergic triggers can help reduce symptoms and the need for medication.5
Persistent Asthma: Daily Medication
Common Symptoms: nighttime awakenings, cough, wheeze, shortness of breath, tightness in the chest
|Risk of Severe Asthma Exacerbations and/or
History Suggestive of Food Allergy
Adapted from the National Asthma Education and Prevention Program. Expert Panel Report 3 (EPR-3): Guidelines for the Diagnosis and Management of Asthma-Summary Report 2007 5 and Guidelines for the Diagnosis and Management of Food Allergy in the United States: Summary of the NIAID-Sponsored Expert Panel Report8
Up to 80% of patients with allergies are sensitized to more than one allergen.9 The effect is cumulative: An individual patient may have a number of triggers, which, combined, may lead to symptoms.10 The allergen symptom threshold is the point at which the cumulative allergen load leads to symptoms.10
Each patient has a different level of IgE antibodies at which he or she will show symptoms. Until the symptom threshold is reached, the patient will not show symptoms. However, when these allergens add up, they have a cumulative effect, pushing the patient over his or her symptom threshold.10 By reducing exposure to certain triggers, symptoms can be avoided.10
Identifying and reducing exposure to sensitized allergens, particularly house dust mite, can reduce the risk of virally-induced asthma exacerbations.15 In patients with asthma, allergies and respiratory viral infections act synergistically – pushing the patient over their symptom threshold – to increase the risk of a severe exacerbation.15 Patients with asthma and allergy, who subsequently develop a respiratory viral infection, are at increased risk of hospital admission.15
Before exposure reduction10,11
More than 80% of people with asthma also suffer from rhinitis,16 suggesting the concept of ‘one airway one disease.17,18 The presence of allergic rhinitis commonly exacerbates asthma, increasing the risk of asthma attacks, emergency visits and hospitalizations for asthma.18-22 It is not clear whether allergic rhinitis represents an earlier clinical manifestation of allergic disease in atopic patients who will later develop asthma or whether rhinitis itself is causative for asthma.17-21
One study has demonstrated that allergen exposure reduction can lead to 61% medication reduction in patients with asthma.11
Identifying all the relevant sensitizing allergens will help you outline a comprehensive exposure reduction plan to keep your patient below his or her symptom threshold. Help your patients assess their environments with these tips for reducing exposure to allergic triggers >
After exposure reduction12-14
A study in approximately 900 children with asthma, published in the New England Journal of Medicine, showed that implementing comprehensive avoidance plans (including education and advice on cleaning and physical barriers) which are targeted at all positive allergens can lead to:14
unscheduled visits per year
days with symptoms per year (19.5%)
missed school days per year
When taking blood for a test a 1 ml sample of whole blood is usually sufficient to test for up to 10 different allergens, although up to 3.5ml of serum is required for some respiratory profiles.
ImmunoCAP Whole Allergen testing provides an objective measurement of the circulating specific IgE antibodies and the sensitization to a specific whole allergen. Specific IgE antibodies can appear as a result of exposure to an allergen in atopic individuals. ImmunoCAP Whole Allergen measure IgE antibodies to specific allergens in human serum or plasma and allows quantitative measurements of a wide range of individual allergens. Over 550 different allergens are available for determinations.22
ImmunoCAP Allergen Components measure specific IgE antibodies to individual molecular allergens, in either serum or plasma. These allergens, which are purified, native or recombinant proteins, offer the unique opportunity to assess a person’s allergic sensitization pattern at the molecular level. Different component groups often elicit different types of reactions, so testing them can indicate if a patient’s prior symptoms or positive test results were caused by allergy to a species-specific substance or by a cross-reaction with another allergen. Component testing can also help identify patients who may be good candidates for supervised oral food challenges. Over 100 different allergen components are available for determinations.22
The higher the concentration of slgE antibodies, the higher the risk for symptomatic allergy23,24,25
Guided by IgE-mediated test results, an individual plan to manage and treat the allergy can be tailored, in order to achieve improved quality of life and overall well-being.
Results should be read in conjunction with the clinical history.24 Patients should be provided with a personalized asthma action plan, including exposure reduction advice for all their confirmed triggers.1
Most patients with asthma have multiple allergic sensitizations (perennial and seasonal aeroallergens etc.) contributing to their allergen load;9,10 these allergen sensitizations can add to the patient’s trigger load eventually resulting in asthma exacerbations – even from other, non-allergic, triggers.10,11 In patients with asthma and aeroallergy, in addition to pharmaceutical strategies, reducing exposure to sensitized allergens can alleviate or reduce symptoms.7,8, 14,24,25