The inclusion criteria for Psoriatic Arthritis patients are:

1. Patients diagnosed with peripheral Psoriatic Arthritis according to the CASPAR criteria or with axial Psoriatic Arthritis according to ASAS criteria and with at least one of the following:

   1. With active peripheral Psoriatic Arthritis regarding ongoing therapy in one of the following sites: MCP joints 1-5, proximal interphalangeal (PIP) joints of hands 1-5, distal interphalangeal (DIP) joints of hands 2-5, wrists, elbows, knees and ankles/heels and feet, according to any of the following criteria:

      I) DAPSA ≥ 15 and joint inflammation according to the Global OMERACT-EULAR US scoring for synovitis and power Doppler (GLOESS) with a grade at patient level >3,2

      II) With a clinical enthesitis and an active enthesitis (positive power Doppler of any grade), in the clinical symptomatic site, according to the OMERACT US definitions

      III) With active dactylitis (clinical diagnosis made by the physician at the time of baseline visit) and a positive US dactylitis according to the DACTylitis glObal Sonographic (DACTOS) score >3

      IV) DAPSA ≥ 15 and tenosynovitis according to the OMERACT US scoring system for tenosynovitis with a grade >1

   2. With active axial PsA regarding ongoing therapy (ASDAS ≥ 2.1) and active sacroiliitis according to the ASAS MRI definitions

2. Who are eligible according to the current guidelines/regulations to start treatment with UPA and present a favorable risk/benefit profile according to the clinician's opinion for such treatment.

3. Aged older than 18 years.

4. Able to provide informed consent, according to requirements of local IRB/ethics committee.

The inclusion criteria for Rheumatoid Arthritis patients are:

1. Patients diagnosed with RA according to the ACR/EULAR 2010 classification criteria

2. With active Rheumatoid Arthritis according to the following criteria: DAS28-PCR >3.2, and the presence of at least one US finding of the following:

   1. Joint inflammation at hands and wrists according to the Global OMERACT-EULAR (GLOESS) US scoring for synovitis and power Doppler with a grade at patient level >2
   2. One tenosynovitis at hands or wrists, according to the OMERACT US scoring system for tenosynovitis with a grade >1

3. Who are eligible according to the current guidelines/regulations to start treatment with Upadacitinib and present a favourable risk/benefit profile according to the clinician's opinion for such treatment.

4. Aged older than 18 years.

5. Able to provide informed consent, according to requirements of local IRB/ethics committee.

Exclusion Criteria:

1. Patients with any contraindication to Upadacitinib:

   1. women who are pregnant or breastfeeding
   2. active infection
   3. evidence of tuberculosis infection
   4. known infection with human immunodeficiency virus or hepatitis B or C
   5. patients who have current malignancy or history of malignancy in the last 5 years
   6. high cardiovascular risk
   7. high risk of venous thromboembolism
   8. patients with severe hepatic impairment

2. Patients with associated fibromyalgia syndrome according to the 2016 ACR diagnostic criteria

3. Unable to provide informed consent, according to requirements of local IRB/ethics committee.

History of severe allergic reactions to study medication Currently pregnant or breastfeeding Recent participation in another clinical trial within the last 30 days Presence of uncontrolled medical conditions that could affect safety