adenosine deaminase activity (ADA) has been reported to be elevated in various diseases such as psoriasis, acne and juvenile idiopathic arthritis. There is no previous studies that assessed ADA in chronic spontaneous urticaria (CSU) .

Inclusion Criteria:

• adult patients complaining of CSU and a group of age and sex-matched healthy controls (blood donors).

Exclusion Criteria:

• Pregnancy and lactation.
• Patients with systemic diseases, especially those with autoimmune diseases and infections.
• Patients with skin diseases.
• Patients on medications such as antibiotics, nonsteroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, anticonvulsants, penicillin, and combined oral contraceptives.

Settings: Dermatology outpatient clinics and Central Research Lab at Sohag University.

Study population: The study will include adult patients complaining of CSU and a group of age and sex-matched healthy controls (blood donors).

IPD will be shared upon request to the study director

Data will become available after study due for unlimited period of time.

IPD will be shared upon request by the study director. Patients' names will be anonymous.