The clinical symptoms of chronic urticaria are a maculopapular rash, both flat or raised lesions on the skin, pruritus and angioedema (swelling without any redness).
The challenge for the clinician is to assess the severity of the urticaria on a daily basis in order to adjust treatment effectively. Tools have been developed to allow the patient to quantify their clinical condition daily.
The UAS score allows the extent of urticarial rash and pruritus to be graded daily by quantifying the severity of each component (rash + pruritus) on a scale of 0 to 3 for a maximum of 6, for combined results.
The weekly score most commonly used in practice is the UAS7. It's obtained by adding up the daily scores over 7 days, which gives a result ranging from 0 to 42.
The limitation of this tool is that it doesn't take angioedema into account, though it's present in 50% of patients. Moreover, for about 10% of patients, angioedema is the dominant, if not the only, manifestation of chronic urticaria.
Therapeutic decisions should take these facts into account. A similar tool (AAS) has been developed to measure angioedema and its impact. This should be completed in parallel to the aforementioned grading tool.