HHE Rheumatology and musculoskeletal supplement 2018 | Page 5
rheumatology and
musculoskeletal
Challenges in the management
of psoriatic arthritis
The ability to understand and manage psoriatic arthritis has progressed enormously
over the past few years and we are thus approaching a more personalised approach
Elena Generali MD
Carlo Selmi MD PhD
Division of Rheumatology
and Clinical Immunology,
Humanitas Research
Hospital, Milan, Italy;
BIOMETRA Department,
University of Milan, Italy
Psoriatic disease is a chronic inflammatory
systemic condition affecting up to 3% of the
general population, characterised by skin
psoriasis, and in about 20–40% of patients,
characterised by psoriatic arthritis (PsA), which
may also be diagnosed in the absence of a
personal history of psoriasis. 1 PsA, different from
rheumatoid arthritis, affects both sexes with
equal frequency, albeit with differences in clinical
manifestations. 2 The incidence of PsA is of
approximately 6 per 100,000 per year and the
prevalence is approximately 6–25 per 10,000 in
the general population. 3 The peak of incidence
is around 30–50 years, with skin psoriasis in the
majority of cases preceding the arthritis by an
average of five years; although in 15% of cases,
psoriasis and PsA occur simultaneously, or PsA
PsA is often
undiagnosed/
misdiagnosed
and likely
undertreated
PsA is burdened
by significant
metabolic
comorbidities
Unmet needs
in PsA
Treatments must
aim to prevent
the long-term
outcomes of PsA
PsA must be
treated to the
target of
remission or low
disease activity
precedes the skin manifestation, while,
more importantly, psoriasis is diagnosed
simultaneously with PsA in over 25% of patients. 4
While the diagnosis and management of other
forms of arthritis, particularly rheumatoid
arthritis, are well characterised, taking care of
patients with psoriatic disease in general, and PsA
in particular, manifests numerous challenges and
the major ones are discussed here.
Diagnostic delay
Due to variable manifestations, suspecting and
timely diagnosis of PsA is a major issue in daily
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HHE 2018 | hospitalhealthcare.com
practice. In fact, the diverse clinical features
of PsA often result in delayed diagnosis and
treatment, ultimately leading to reduced
quality of life and elevated risk of cardiovascular
disease, and depression. 5 The major clinical
manifestations can be separated into different
phenotypes: distal arthritis; asymmetric arthritis;
symmetric polyarthritis; dactylitis; enthesitis; and
arthritis mutilans and axial involvement, which
can coexist in the same patient along with skin
and nail psoriasis. 6 PsA can lead to bone erosions
in up to 45% of patients within the first two years.
Spontaneous remission of PsA is extremely rare,
and relapse rates are high when treatment is
discontinued.
The diagnosis of PsA can be only supported by
the CASPAR classification criteria, 7 and is based
on clinical and imaging features that reflect
a later stage of the disease. Unlike rheumatoid
arthritis, there are no known autoantibodies. 8
Thus, a significant diagnostic delay in PsA can be
observed, 9 which can lead to irreversible damage
and permanent disability; therefore establishing
an early diagnosis as one of the key challenges
in the management of PsA. Unfortunately, only
human leukocyte antigen (HLA)-B27 and and
HLA-Cw6 are important markers to identify
patients at higher risk of PsA. 8 However, HLA-B27
is positive in 25% of PsA cases, and increases in
levels of C-reactive protein (CRP) and erythrocyte
sedimentation rate (ESR) can be observed in 40%
of patients. By contrast, several studies are
investigating PsA biomarkers, and the Group
for Research and Assessment of Psoriasis and
Psoriatic Arthritis (GRAPPA) has launched
a biomarker initiative. 10 Recently, serum proteins
(CD5L, ITGB5, M2BP, MPO, MMP3 and CRP) have
been found to differentiate PsA from controls,
whereas CD5L, M2BP and MPO were
independently associated with psoriasis only. 11
To increase the detection of PsA, ideally every
psoriasis case complaining of musculoskeletal pain
should undergo a rheumatological evaluation;
however, this approach is not feasible in every
setting. Therefore, in the past years, a number of
screening tools have been developed to improve
PsA early diagnosis among dermatologists and
primary care physicians. 12 These screening tools
are questionnaires that are feasible in daily
practice and include, among others, the Psoriatic
Arthritis Screening and Evaluation (PASE), the
Psoriasis Epidemiology Screening Tool (PEST),
and the Toronto Psoriatic Arthritis Screening