Psoriatic Arthritis in Nigeria: Case Series and Literature Review

Abstract

Background: Psoriatic arthritis (PsA) is an extracutaneous manifestation of psoriasis occurring in 6% to 42% of patients. Both conditions are common among whites but rarely reported among black Africans.Few African studies, however, have reported PsA frequencies of 0% to 4.6%, with a previous case report of 2 patients from a Nigerian rheumatology clinic.

Methods: Case records of PsA patients from the Lagos State University Teaching Hospital Rheumatology Clinic seen over a 5-year period from January 2012 to December 2016 were retrieved and documented.Psoriatic arthritis was diagnosed using the Classification Criteria for Psoriatic Arthritis. Data on demography, clinical features, laboratory parameters, imaging, and treatment were extracted from case records.

Results: Twelve PsA cases were identified out of 2330 patients (0.5%) seen during the study period. There were 9 males and 3 females. Age range was 24 to 67 years (mean, 45.3 ± 15.1 years). Duration of psoriasis ranged between 11 and 96 months (mean, 46.8 ± 33.6 months), whereas median duration of arthritis at presentation was 15 months (range, 4-72 months).Oligoarthritis was the commonest presentation (58.3%). Dactylitis (66.7%) and enthesitis (44.7%) were frequent extra-articular features. All patients were negative for rheumatoid factor and human immunodeficiency virus. HLAB27 was negative in 5 patients tested.Treatment was mostly with nonsteroidal anti-inflammatory drugs (100%) and methotrexate (75%). Only 1 patient received the biologic etanercept. Eight subjects (66.6%) showed initial improvement in skin and joint symptoms, of which 6 had a relapse within 6 to 12 months.

Conclusions: Psoriatic arthritis is rare among Nigerians and predominantly affects males in their fourth decade. Oligoarthritis is common, and extra-articular manifestations are frequent.