The prevalence of PsA amongst patients with psoriasis is about 30% (6%-43% in various studies).4-6 

The prevalence of psoriatic arthritis amongst patients with psoriasis is about 30%.

PsA is a heterogeneous disease, and that heterogeneity is not limited to the musculoskeletal manifestations but also includes cutaneous manifestations. Because of these highly variable clinical presentations, the diagnosis of PsA can be challenging for those not experienced in the field. 7,8

The diagnostic criteria for PsA have changed significantly from the 1973 Moll and Wright criteria to the 2006 classification criteria for psoriatic arthritis (Casper criteria).7,8

The latest classification criteria have made significant inroads into unifying the diagnosis of PsA globally. Despite these advances in PsA, there are still significant unmet needs in its diagnosis and management in South Africa.

Education

One of the major stumbling blocks in the improvement of diagnosis and management of PsA in South Africa is the lack of academics dedicated to the field of PsA/spondyloarthritides.

None of the academic universities/medical schools in South Africa have dedicated PsA experts that can stand shoulder to shoulder with global experts. This fact has a negative impact on:

  • The training of rheumatology fellows/trainees exiting as rheumatologists from these academic institutions. Young rheumatologists are lacking in the assessment and management of PsA, as well as holistic management of these patients regarding comorbidities
  • The interest in the field of PsA/spondyloarthritides is not inculcated in junior doctors at a very early stage of their career.

Delay in diagnosis

A six-month delay in diagnosing PsA results in radiographic progression with damage and poorer outcomes.9

The delay in diagnosis often results from the absence of a specific diagnostic test for PsA, the heterogeneous phenotypes, and the late referral to a rheumatologist.

A lack of rheumatologists in South Africa is another primary unmet need. There is about one rheumatologist per 630 000 people. A further challenge is that most assessment tools in PsA have not been validated in South Africa, especially their applications to patients speaking indigenous languages.

Tools to predict the development of psoriatic arthritis

There are no clinical or soluble biomarkers that can predict which patients with psoriasis will develop PsA. It is incumbent on the treating physician to have a high index of suspicion and screen patients for PsA for early referral to a rheumatologist. Inflammatory markers such as C-reactive protein may assess the primary care physician in screening purposes for early referral to a rheumatologist.10

Imaging

Advanced imaging like musculoskeletal ultrasound and magnetic resonance imaging are not readily available at all centres in the country. These imaging modalities can assist in the early diagnosis of PsA.11

The problem with plain radiographs is that it is late in the disease course when damage occurs, and plain radiographs have a limited role in detecting early disease.

Drug treatment

The South African Arthritis and Rheumatism Association currently has no treatment recommendations to guide primary care physicians and rheumatologists in managing patients with PsA. Most of the treatment recommendations that are followed locally are tailored from international recommendations, including the European League of Associations of Rheumatology or the Group for Research and Assessment of Psoriasis and PsA treatment recommendations, which may not always be beneficial for our patients.12,13

Due to South Africa being a developing country with cost constraints, our first line of therapy in PsA is conventional synthetic disease-modifying agents (csDMARDs). The csDMARDs may not cover all the domains in PsA and are ineffective in pure axial involvement. Biologic disease-modifying antirheumatic drugs are accessible to a small proportion of the population with private healthcare insurance/medical scheme membership. They are not accessible to most patients that are attending government institutions.

Holistic management

There is a lack of consultation between dermatologists and rheumatologists, in the main. Very few centres in South Africa have combined dermatology/rheumatology clinics for patients with PsA. Also, PsA is associated with various extra-articular manifestations and comorbidities that require holistic management.

By and large, these patients will benefit from a multidisciplinary team approach, including dermatologists, cardiologists, endocrinologists, physiotherapists, occupational therapists, and psychologists.14 The coordinator of this team should be the rheumatologist.

Rheumatology nurses

There is a lack of dedicated rheumatology nurses in both the private and public sectors in South Africa. Rheumatology nurses play an important role in educating and communicating with patients. They form a bridge between the busy physician and the patient. The education of nurses in this vital field is of paramount importance.

Patient factors

Many patients do not associate musculoskeletal symptoms with cutaneous manifestations. There is a delay in patients with PsA addressing their musculoskeletal symptoms. Most patients concentrate on the cosmetic effect of cutaneous manifestations and pay little attention to musculoskeletal manifestations.

This results in a delay in communicating their musculoskeletal symptoms to their dermatologists/primary care physicians resulting in a delay in diagnosis. Patient education in this regard is of paramount importance to make early diagnoses and improve outcomes.

Strategies to address unmet needs

Strategies to address the unmet needs in patients with PsA require a multi-dimensional approach. Education must be multifaceted, including doctors, nurses, and patients. There is emerging evidence that weight reduction and lifestyle changes improve outcomes in patients with PsA.15

This makes patient education even more critical. A multidisciplinary team approach needs to be advocated and implemented.

REFERENCES:
  1. Gelfand JM, Weinstein R, Porter SB, et al. Prevalence and treatment of psoriasis in the United Kingdom: a population-based study. Arch Dermatol, 2005;141:1537–1541.
  2. Brandrup F, Green A. The prevalence of psoriasis in Denmark. Acta Derm Venereol, 1981;61:344–346.
  3. Ferrandiz C, Bordas X, Garcia-Patos V, et al. Prevalence of psoriasis in Spain (Epiderma Project: phase I). J Eur Acad Dermatol Venereol, 2001;15:20–23.
  4. Gelfand JM, Gladman DD, Mease PJ, et al. Epidemiology of psoriatic arthritis in the population of the United States. J Am Acad Dermatol, 2005;53(4):573–577.
  5. Taylor WJ. Epidemiology of psoriatic arthritis. Curr Opin Rheumatol, 2002;14:98–103.
  6. Alamanos Y, Voulgari PV, Drosos AA. Incidence and prevalence of psoriatic arthritis: A systematic review. J Rheumatol, 2008;35:1354–1358.
  7. Moll JM and Wright V (1973). Psoriatic arthritis. Semin Arthritis Rheum 3: 55–78.
  8. Taylor W, Gladman D, Helliwell P, et al. CASPAR Study Group. Classification criteria for psoriatic arthritis: development of new criteria from a large international study. Arthritis Rheum, 2006;54:2665-73.
  9. Haroon M, Gallagher P, Fitzgerald O. Diagnostic delay of more than six months contributes to poor radiographic and functional outcome in psoriatic arthritis. Ann Rheum Dis, 2015;74:1045e50.
  10. Chandran V, Cook RJ, Edwin J, Shen H, Pellett FJ, Shanmugarajah S, et al. Soluble biomarkers differentiate patients with psoriatic arthritis from those with psoriasis with arthritis. Rheumatology, 2010;49(7):1399e405.
  11. D’Angelo S, Palazzi C, Gilio M, Leccese P, Padula A, Olivieri I. Improvements in diagnostic tools for early detection of psoriatic arthritis. Expert Rev Clin Immunol, 2016;12(11):1209e15.
  12. Gossec L, Baraliakos X, Kerschbaumer A, et al. EULAR recommendations for the management of psoriatic arthritis with pharmacological therapies: 2019 update. Annals of the Rheumatic Diseases, 2020;79:700-712.
  13. Coates LC, Kavanaugh A, Mease PJ, et al. Group for Research and Assessment of Psoriasis and Psoriatic Arthritis 2015 treatment recommendations for psoriatic arthritis. Arthritis Rheumatol,2016;68:1060–71.
  14. Haberman R, Perez-Chada LM, Merola JF, Scher J, Ogdie A, Reddy SM. Bridging the gaps in the care of psoriasis and psoriatic arthritis: the role of combined clinics. Curr Rheumatol Rep, 2018;20(12):76.
  15. Fortune DG, Richards HL, Kirby B, Bowcock S, Main CJ, Griffiths CEM. A cognitive-behavioural symptom management programme as an adjunct in psoriasis therapy. Br J Dermatol 2002;146:458e65.