579 The Frequency of Positivity in Autologous Serum Skin Test in Patients with Chronic Idiopatic Urticaria

BACKGROUND: Describe the frequency of positive results in autologus serum skin test among patients with cronic urticaria. METHODS: Trans-sectional study of patients with CIU refered to traitment in policlínica geral do Rio de Janeiro, brazil. Autologus serum intradermal injections were used to estabilished the sensitivity. Negative and positive controls were made with 0.9% intradermal saline solution and skin prick test with histamina 1:100 solution. Autoreactivity was considered positive when wheal reached 3 mm at least, 1.5 mm larger than saline solution at 30 minute interval. Antihistamines drugs were interrupeted 72 hours before test. Dates on race, age, sex, and informations about length and how often the symptoms persist, personal history of atopy (PHA) and angioedema (AE), autoimmune disease (AID) and physical (PF) and not physical factors (NPF) related with the worsening of urticaria were registered during appointment. K square and τ student tests were used in this work. RESULTS: Eighteen patients, from 2008, march to 2011, march, were investigated (15 f; 12 w; age 50,67 ± 16,93 yr). Eleven patients presented positive AAST (61.1%) with a mean wheal diameter = 9,64 ± 2,66 mm (negative control = 6,33 ± 3,63 mm; P < 0,001). All of the positive asst occurred in patients over 60 years old. The mean length of the desease was 21,78 ± 22,95 months. Continuous symptoms were saw in 83.3%, pruritus, the major one (94.4%). Angioedema and PHA were present in 61.1% and 27.8%, respectively. NPF of symptoms worsening like drugs, food, emotional stress or alcoholic beverages were complaint of 72.2% of individuals, whereas 22.2% complainted about worsening with colinergic PF or dermographism. Joint pain (33.3%) were the complain the most frequent and 7 patients, mainly whose with positive ASST, had elevated thireoid antibody levels (n = 5; P > 0.05). CONCLUSIONS: The positive asst frequency was 61%, comparable to values found in the liretature. Association among social-demographic and clinical aspects was not observed. We emphasize the prevalence of joint pain and angioedema as associated symptoms and the more frequence of AID laborotory finds. The procedure proved safe and precise and worth value in the screening diagnosis of autoimune etiology for patients with CIU.