urticaria activity score

Last edited 02/2023 and last reviewed 03/2023

The Urticaria Activity Score (UAS) is a composite score of itch severity and hive count

The Urticaria Activity Score (UAS) is a commonly used diary-based patient-reported outcome (PRO) measure that assesses the key sign (hives) and symptom (itch) of CSU (chronic spontaneous urticaria) (1)

• two versions of the daily UAS exist
  • 1) assesses the number of hives and the intensity of itch twice daily (every 12 h), and
  • 2) assesses hive number and itch intensity once daily (every 24 h)
    
    
• both versions can generate a weekly score (UAS7), calculated as the sum of the daily number of hives score and the itch severity score over 7 days. UAS7 values range from 0 to 42, with higher values reflecting higher disease activity
  
  
• the UAS7 is the sum of the average daily UAS over 7 days
  
  
• after 7 days, average daily scores from the morning and evening assessments are added together
  
  
• values can range between 0 to 21 for weekly itch severity, and 0 to 21 for weekly hive count
  
  
• the UAS7 ranges from 0 to 42

Once Daily UAS:

UAS once-daily version: daily scoring for itch and hives

• with the daily UAS7, the person records the severity of itching and the number of weals daily for 7 days. A score of less than 7 in 1 week indicates control of disease, whereas a score of  more than 28 per week indicates severe disease

Click here for an editable version of the UAS7 calculator

Notes:

• study evidence showed that once- and twice-daily UAS7 scores were highly consistent, supporting the use of either version when evaluating CSU activity (1)

Reference:

• Hollis K, Proctor C, McBride D, Balp MM, McLeod L, Hunter S, Tian H, Khalil S, Maurer M. Comparison of Urticaria Activity Score Over 7 Days (UAS7) Values Obtained from Once-Daily and Twice-Daily Versions: Results from the ASSURE-CSU Study. Am J Clin Dermatol. 2018 Apr;19(2):267-274.