Evaluate Safety and Pharmacokinetics of INF904 in Subjects With Moderate to Severe Chronic Spontaneous Urticaria or Hidradenitis Suppurativa

Inclusion Criteria: * Signed informed consent. * Subjects must be 18 years or older at the time of signing the informed consent. Exclusion Criteria: * Subjects with known severe or life-threatening hypersensitivity reaction to any other CSU/HS treatment according to National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE). * Subjects who have any other skin disease that may interfere with assessment of CSU or HS. * Subjects who have an active infection or history of infection(s) as follows: 1. Any infection requiring systemic treatment within 14 days prior to baseline. 2. A history of opportunistic, recurrent, or chronic infections that, in the opinion of the Investigator, might cause this study to be detrimental to the subject. * Subjects with known progressed liver disease (Child-Pugh B or C)