Case Report and Literature Review of : Difficult-to-Treat Arthritis in Hiding.

Septic arthritis is a life-threatening rheumatological syndrome that is highly related to a patient's immune status and comorbidities, and although the most common clinical presentation is rapid-onset monoarthritis, it can also appear as subacute or chronic joint swelling. In these cases, differential diagnosis is more challenging, but early diagnosis and treatment is no less urgent to ensure a good global prognosis and the best outcome of the affected joint. Anaerobic microorganisms, such as , are an uncommon cause of septic arthritis (less than 5% of cases) but may be the cause of subacute arthritis.

HLA-Cw6 allele and biologic therapy are protective factors against liver fibrosis in psoriatic arthritis patients.

Objectives: To evaluate the association between liver fibrosis and the HLACw6 allele in psoriatic arthritis (PsA) patients.

Methods: A retrospective longitudinal study involving PsA patients with determination of the HLA-Cw6 allele was performed. Liver fibrosis was estimated by using the FIB-4 (fibrosis-4) score.