Psoriatic arthritis (PsA) is a seronegative systemic disease that belongs to the family of spondyloarthropathies. Its worldwide prevalence ranges from 0.05% to 1%, and it appears in 10-40% of patients with skin psoriasis; however, it is believed to be underdiagnosed. More than 80% of patients who are diagnosed with PsA already have skin disease, mainly in the form of plaque psoriasis. However, 15% of patients present with musculoskeletal involvement prior to psoriasis which makes the diagnosis of PsA challenging. It is important to do a thorough clinical assessment, take a family history and actively look for evidence of psoriasis: this includes examining nails, the scalp, intergluteal region and umbilicus.