Psoriatic arthritis in patients with psoriasis: evaluation of clinical and epidemiological features in 133 patients followed at the University Hospital of Brasília.

BACKGROUND: Psoriatic arthritis is an inflammatory arthritis associated with psoriasis. Its prevalence in patients with psoriasis varies from 7 to 42% but its exact prevalence is unknown.
OBJECTIVES: Considering the lack of national data related to its diagnosis in patients with psoriasis, this study aims to describe the clinical, laboratorial and radiological manifestations of psoriatic arthritis in these patients.
METHODS: We evaluated 133 patients with psoriasis, treated as outpatients. These patients were asked to fill in the forms with data about the disease and were submitted to a clinical evaluation by a dermatologist and a rheumatologist. Suspected cases of arthritis were referred for further investigation and were classified according to presence or absence of psoriatic arthritis according to CASPAR criteria.
RESULTS: The number of patients with psoriatic arthritis was 47 (35%), 17 of them were new cases. There was no difference between the groups regarding the type of psoriasis, nail involvement, presence of scalp lesions and psoriatic arthritis. Patients with psoriatic arthritis had more enthesitis and dactylitis (46.7%) than those without arthritis.
CONCLUSIONS: Despite the high prevalence of arthritis found, we know that results from epidemiological studies are variable, which limits their use and interpretation. We conclude that more studies are needed to draw a profile of rheumatic manifestations in our population of psoriasis patients.