ABSTRACT
Background: The diagnosis of drug allergy requires a previous medical history suggestive of a Drug Hypersensitivity Reaction (DHR). DHRs caused by vaccines are rare (< 1/100.000 doses) and are mainly due to excipients. At the beginning of the COVID-19 vaccination, occasional cases of severe reactions were reported in patients with allergy history. This warning led to an increased demand for allergy testing to evaluate pre-vaccination risk assessment, especially due to the refusal of allergic patients to receive the vaccine. Method(s): Twenty patients were evaluated between May to July 2021, referred for allergology study prior to receiving the vaccine against COVID-19. All patients tested had allergy history. Skin tests were performed with the available excipients of the COVID-19 vaccine: polyethylene glycol (PEG-1500, 10% prick ROXALL), polysorbate 80 (tween 80 prick 0.04 -ID 0.004 mg/ml), and trometamol (prick 1 -ID 0.1 mg/ml). A telephone follow-up was subsequently performed to assess tolerance to the vaccine. Result(s): The median age of the patients was 54.5 years and ninety percent were female. (Table 1) The most frequent allergy history was adverse drug reactions (ADRs) in 18 patients (90%), followed by bronchial asthma (35%), rhinitis (25%), food allergy (25%), and dermatitis (15%). 12 patients (60%) had multiple allergic diseases. The drugs implicated in these ADRs were beta-lactam antibiotics (40%), NSAIDs (20%), radiographic contrast media (15%), and vaccines (15%). Skin tests with the excipients studied were negative in all cases. Subsequently, the COVID-19 vaccine was administered in 16 patients (80%). Six patients (30%) reported side effects expected from the vaccine and no DHRs were described. Although vaccination was recommended to all patients after the study, 4 patients (20%) refused the administration. Conclusion(s): Patients with atopic history do not require an allergology study prior to the administration of the COVID-19 vaccine. Exceptionally, it may be necessary if the patient has a history of suspected DHRs to the excipients involved. The previous allergology assessment did not prevent refusal of vaccination in 20% of the patients. (Table Presented).
ABSTRACT
Background: Inducible Urticaria (IU) is a type of Chronic Urticaria (CU) that occurs after exposure to physical and non-physical stimuli The diagnosis is based on patient history and provocation tests, which reproduce the symptoms after exposure to an appropriate triggering stimulus. IU may be present in patients with history of Chronic Spontaneous Urticaria (CSU) Our objective was to establish standardized protocols through diagnostic circuits that included tests for different stimuli in the same visit, reduce consultation time and evaluate their effectiveness and safety. Method: We designed 4 circuits where different test instruments for IU were included: Temptest, Fric-Test, Calibrated Dermographometer, Standard laboratory vortex and suspension of weights (7 kg.) over the shoulder. The circuits were: • Basic Circuit (BC): Dermographism, Temperature (cold and heat), Pressure (delayed an acute) and Vibratory Urticaria (Diagram 1) • Cold Urticaria Circuit (CUC): CB plus Ice Cube Test • Aquagenic Urticaria Circuit (AqUC): CB plus Aquagenic test • Autoimmune Urticaria Circuit (AuUC): CB plus Autologous Serum Skin Test (ASST) Cholinergic Urticaria tests were not included due to COVID pandemic restrictions, nor tests for Solar Urticaria as the necessary technical means were not available. For 6 months, we selected 51 patients with urticaria history lasting for more than 6 weeks. The circuit chosen for the study depended on the initial clinical suspicion. If there was no clear triggering stimulus, the BC was performed which includes the most frequent causes of IU. Results: Of the total number of patients studied, BC was applied to 82.4%, CUC to 7.8%, AqUC to 7.8% and AuUC to 2%. The most frequent diagnosis was Dermographism in 47.05% of the patients. This diagnosis was also present in some patients with CSU. The maximum time to perform these circuits was 30 minutes. None of the patients studied presented systemic reactions, anaphylaxis or other unexpected reactions. Conclusion: We observed that the use of standardized circuits in patients with suspected UI makes it possible to study more than one stimulus and to give the appropriate recommendations in each case. These tests are easy to apply and help to optimize study time. Besides, they allow the detection of physical or non-physical stimuli associated with SCU. Given that no patient presented adverse reactions, it appears to be a safe test. (Figure Presented).