• Signed informed consent must be obtained prior to participation in the study.

• Male and female participants ≥ 18 years of age at the time of signing of the informed consent forms.

• CINDU patients: Confirmed diagnosis of CINDU with a duration of ≥ 4 months (defined as onset of CINDU with supporting documentation (e.g. medical record, clinical history, photographs) and inadequate control with H1-AH at local label approved doses at the time of randomization. The response to the provocation test for each CINDU subtype is required before randomization (either during screening or prior to randomization on Day 1):

• CINDU patients: Patients should be symptomatic for their most bothersome symptom as assessed with the USDD during baseline with a NRS score of 3 or more

• CSU patients: Diagnosis of CSU (acc. to Zuberbier et al 2022c) not adequately controlled with H1-AH at approved doses alone for at least 4 weeks prior to randomization, as defined by all of the following:

‣ UAS7 score (range 0-42) ≥ 16 and HSS7 (range 0-21) ≥ 8 during 7 days prior to randomization

⁃ CSU for ≥ 6 months

• Participants must be willing and able to attend the protocol defined test procedure throughout the study.