![]() There were 10 patients (10.1%) who were lost to follow-up after their provocation tests. He subsequently received omalizumab for five months with a good response and was subsequently lost to follow-up. One patient with cholinergic urticaria did not respond to H1 antihistamines (fexofenadine) despite a four-fold increase in the dose. One patient with cold urticaria responded well to a combination of H1 and H2 antihistamines (desloratadine and cimetidine), while another with cold urticaria required the addition of a leukotriene receptor antagonist (montelukast). Patient education was also done in our subspecialty clinic to provide strategies to avoid potential physical triggers. ![]() In cases where physical triggers were unavoidable, patients were advised to take antihistamines at least one hour prior to exposure to prevent the recurrence of symptoms. He was nonetheless prescribed standby epinephrine on clinical grounds and was referred to an allergist.Įighty-six out of the 99 (86.9%) of our patients with at least one positive provocation test achieved quiescent disease subsequently with avoidance of the identified trigger along with regular use of H1 antihistamines up to a four-fold increase in the dose. Another patient had a clinical history suggestive of food-dependent exercise-induced anaphylaxis, although his exercise test was negative. His final diagnosis was idiopathic angioedema. One patient had a history of angioedema with exercise although his exercise provocation test was negative. Four were eventually diagnosed with more than one CIndU (one each with cholinergic and cold urticaria, cold urticaria and symptomatic dermographism, cholinergic and heat urticaria, and heat and delayed pressure urticaria). Ninety-nine out of 168 (58.9%) of the patients referred for provocation tests had at least one positive result. * Numbers exceed 100% due to >1 types of suspected CIndU per patient The most common suspected CIndU referred for provocation testing was cholinergic urticaria ( n = 92, 54.8%), followed by cold urticaria ( n = 57, 33.9%), heat urticaria ( n = 15, 8.9%), solar urticaria ( n = 8, 4.8%) and aquagenic urticaria ( n = 4, 2.4%). The mean duration from symptom onset to the formal diagnosis of their CIndU was 41.4 months (range 2–240 months). There was a predominance of males ( n = 140, 83.3%) compared to females ( n = 28, 16.7%). Immersion in a 42 oC bath for 15 min after recording a rise in body temperature of 1 oC above baseline.Ī total of 168 patients underwent provocation testing during the study period. Exercise on a bicycle trainer for 30 min2. Immersion of either volar forearm in water for 5 minġ. Placement of either volar forearm on a laboratory vibrator plate, vibrate at 1000 rpm for 10 min UVA 6 J/cm 2 and UVB 60 mJ/cm 2 to separate buttocks, and visible light to either upper arm Suspension of 7 kg of weights over either shoulder with a 3 cm strap for 15 min Melting ice cube in a thin plastic bag, applied onto either volar forearm for 5 minīeaker of water at 45 oC, applied to either volar forearm for 5 min Moderate stroking of either volar forearm skin with a closed ballpoint pen tip Tests were performed at sites unaffected by urticaria in the last 24 hours. Consumption of medications used to treat urticaria was deferred for at least three days in the case of antihistamines, or at least seven days in the case of other medications (including glucocorticoids). 1 Prior to testing, informed consent was obtained from all patients. Table 1 summarises the methodology used for provocation tests. The study was approved by the local ethics committee. Cases were excluded if they had been diagnosed with another urticaria-related condition such as urticarial vasculitis, hereditary periodic fever syndrome or acquired autoinflammatory syndrome. Their electronic medical records were reviewed and the following data were collected: age, gender, occupation, type(s) of CIndU, disease onset, results of their physical challenge tests and response to treatment given. Cases that fulfilled the definition of chronic urticaria were enrolled and a provocation test was performed if they were suspected of having one or more CIndU. This is a retrospective analysis of patients who were referred to the urticaria clinic of our centre between January 2012 and December 2017. 1 We describe our 5-year experience of performing provocation tests for patients with suspected CIndU at our tertiary dermatological centre in Singapore. Chronic inducible urticaria (CIndU) is a sub-group of chronic urticaria in which wheals and/or angioedema develop in response to specific stimuli.
0 Comments
Leave a Reply. |