The Autologous Serum Skin Test as a Prognostic Factor for the Severity and Duration of Chronic Urticaria after five years of Follow-up

RATIONALE: The autologous serum skin test (ASST) has been widely used to try to demonstrate autorreactivity in chronic urticaria (CU), but the possible correlation with the long-term clinical course of the disease is unknown. Our objective was to evaluate if there were clinical and sociodemographic differences between patients affected by CU after five years of follow-up, according to the positive or negative results of the ASST.

METHODS: Clinical and sociodemographic data of patients diagnosed with CU and ASST performed in our hospital between 2009 and 2014, were reviewed. Age, gender, refractoriety to treatment, disease duration, development of thyroiditis and other autoimmune diseases were analyzed and compared between the positive (ASST+) and negative (ASST-) ASST groups.

RESULTS: 71 patients, 50 females and 21 males, with an average age of 52.8 years were selected. There were no significant differences in age and sex between the groups. In the ASST+ group, 45% of CU were refractory to the standard treatment (double dose of antihistamines) and 81% of CU were persistent after 3-5 years vs. 6% and 21% in the ASST- group, respectively. After five years, 25% of ASST+ patients were diagnosed with an autoimmune disease and 25% of these had autoimmune thyroiditis vs. 8.5% and 14%, respectively, for ASST- patients. Helicobacter Pylori was detected in 60% of ASST+ patients vs. 4.7% of ASST- patients.

CONCLUSIONS: ASST could represent a useful and cheap tool as a prognostic factor for the duration and severity of CU in clinical practice, although further investigation is needed.