The definition of CSU and classification of chronic urticaria.
CSU is defined as the spontaneous appearance of wheals, angioedema or both, lasting for more than 6 weeks. The cause is unknown.
Urticaria may be classified into different subtypes based on duration and cause:
Classifying chronic urticaria1
Adapted from Zuberbier T et al. 2018.1
- Zuberbier T et al. Allergy 2018;73(7):1393–1414.