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Understanding the instigating factor and getting the most comprehensive diagnosis for patients with urticaria may involve identifying any underlying and contributing allergies. In general, allergic triggers can be identified in between 60-80% of acute urticaria patients.1
If your allergy-focused patient history finds strong symptoms or a history of sensitizations, current guidelines recommend diagnostic testing.2 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||YES||YES|
|Patients do not need to discontinue allergy medications||YES||NO|
|Requires only on needle stick (a single blood sample)||YES||NO|
|Carries no risk of severe allergic reaction||YES||NO|
|Can be used when extensive skin rash is present||YES||NO|
|Component testing is available
|Same day results in office||NO||YES|
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.
Urticaria occurs when mast cells and basophils in the superficial dermis release histamine and other vasoactive substances.2 This can be either an immune- or nonimmune-mediated response.2
|Immune-mediated mast cell activation||Nonimmune-mediated mast cell activation|
When clinically assessing patients with urticaria, healthcare professionals should seek to identify potential trigger factors including:8
When it comes to chronic urticaria, a common cause is an autoimmune disorder.9
House Dust Mite
Excluding foods that cause allergic reactions has been shown to reduce symptoms;6 healthcare professionals can utilize specific IgE testing to enhance the diagnostic process and pinpoint those allergens. The specific information gleaned from test results can also be used to develop a personalized treatment plan.
Suspicion of Allergy
Allergy-like symptoms + Case history
Confirm/Identify Relevant allergens
ImmunoCAP Whole Allergen testing with relevant allergens*
0.1 kUA/l >100
Risk of symptomatic allergy increases with increase in lgE anti-body level. 21,22
|Test interpretation: Negative|
|Test interpretation: Positive|
*Symptom profile containing relevant allergens. Local adaptation with respect to age and regional differences is recommended.
** The lgE antibody level should be regarded as additional information helping the clinician confirm the clinical decision, based also on a case history and physical examination.
*** Factors to consider for a final diagnosis: age, degree of atopy, allergen load, type of sensitizing allergens, previous symptoms, other triggering factors.
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.<>
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.7
The higher the concentration of lgE antibodies, the higher the risk for symptomatic allergy8
Guided by the IgE-mediated test result, 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;9 patients should be provided with a personalized asthma action plan including exposure reduction advice for all their confirmed triggers.
Allergy-related acute urticaria can be difficult to identify and manage as poly-sensitization is common. Up to 80% of patients are sensitized to more than one allergen.10 Furthermore, identifying the obvious allergen is not always enough. Allergic responses can develop to previously tolerated substances, and sensitization to seasonal and perennial allergens often add up to symptoms.