[[Translated article]]Erythema, Localized Edema and Heat vs Forearm Perimeter Increase. Time to Revise the Consensus Recommendations on the Vortex Provocation Test in Vibratory Urticaria-Angioedema?

Abstract

Background and objective: Vibratory urticaria/angioedema is confirmed by the vortex provocation test. It has been agreed to measure the perimeter of the forearm after exposure to the vortex to define a positive response to it.

Material and method: We evaluated the frequency of prior symptoms following vibratory stimuli in volunteers (using a questionnaire); the response to the vortex test in the same volunteers (increase in forearm perimeter, erythema, localized edema, heat, and pruritus); inter-rater reliability; and, the correlation between the questionnaire score and the response to the test.

Results: 140 volunteers participated. 17 were excluded due to dermographism. Of 123 without dermographism, 59% responded affirmatively to ≥1 item of the questionnaire. Localized erythema, heat or localized edema were observed in 58.5%; 38.2%; and 32.5%, respectively. 73,6% presented with itch. Mean intensity of itch was 3.44 95% CI (2.94-3.94). Interrater agreement was low regarding the increase in forearm circumference at three levels (intraclass correlation coefficient: 0.477 95% CI: 0.253-0.634; 0.496 95% CI: 0.280-0.647; and 0.370 95% CI: 0.100-0.559, respectively); and, optimal regarding erythema, heat and localized edema (Kappa index: 0.868; .756; and .757, respectively). A significant correlation was identified between the questionnaire score and the altered response to the test in its different variables.

Conclusions: We propose the variables: erythema; localized edema; heat; and, the intensity/speed of onset/duration of pruritus, to define a positive response to the vortex test given their ease of execution and the optimal inter-observer agreement.