Characterising the axial phenotype of psoriatic arthritis: a study comparing axial psoriatic arthritis and ankylosing spondylitis with psoriasis from the REGISPONSER registry

Comparative Characteristics of Axial Spondyloarthritis and Psoriatic Arthritis with Axial Involvement

of the study was to compare clinical characteristics of patients with axial spondyloarthritis (axSpA)/ankylosing spondylitis (AS) and with axial psoriatic arthritis (axPsA). MATERIALS AND METHODS: . A total of 100 patients were examined: 45 with axSpA/AS (group 1) and 55 with axPsA (group 2). Patients of group 1 were included according to axSpA/AS criteria; patients of group 2, according to CASPAR (ClASsification criteria for Psoriatic ARthritis) criteria, and having axial involvement (axPsA). Axial involvement was detected in case of radiologically significant sacroiliitis (SI, bilateral grade ≥2 or unilateral grade ≥3), or active MRI significant sacroiliitis, or ≥1 syndesmophyte(s) of the cervical and/or lumbar spine. Patients were evaluated for the presence of inflammatory back pain (IBP) by ASAS (Assessment of Spondyloarthritis International Society) criteria. RESULTS AND DISCUSSION. : Patients of group 1 were younger (p < 0.001), more often were HLA-B27 positive (p < 0.001), and more often had IBP (p = 0.001). Patients of group 2 had older age (> 40 years) at back pain onset (p < 0.001) and more often had peripheral arthritis (p < 0.001), dactylitis (p = 0.004), and skin psoriasis (p < 0.001). Nail psoriasis was found only in group 2 patients (p < 0.001). Group 1 patients more often had heel enthesitis (p = 0.005). Group 2 patients had worse axial disease activity scores: BASDAI (Bath Ankylosing Spondylitis Disease Activity Index; p = 0.006) and ASDAS-СRP (Ankylosing Spondylitis Disease Activity Score with C-reactive protein level determination; р < 0.001); and worse patient-reported outcomes: BASFI (Bath Ankylosing Spondylitis Functional Index; p = 0.004), patients' pain (p = 0.005) and patients' global assessments (p = 0.036). Patients of group 2 had more syndesmophytes of the lumbar (р = 0.009) and cervical (р = 0.007) spine. Only in group 2 patients, chunky "non-marginal" syndesmophytes (in 32.1%), as well as spinal lesions without sacroiliitis (in 20.0%) were found. Patients of group 2 had more joint erosions (р = 0.001), osteolysis (р = 0.015), juxta-articular bone formation (р < 0.001) and joint ankyloses (р = 0.02). All patients of group 1 and only 80% of group 2 (р = 0.003) met ASAS criteria for axSpA. AxSpA/AS and axPsA seem to be two different diseases. In our cohort of patients, axPsA patients had worse disease status compared to axSp and AS.

The 'Tree trunk and root' model: key imaging findings may anatomically differentiate axial psoriatic arthritis and DISH from axial spondyloarthropathy

Variable axial skeleton inflammation and axial skeleton tissue remodelling with aberrant ligamentous soft-tissue ossification occurs across the axial spondyloarthritis (ax-SpA) axial psoriatic arthritis (ax-PsA) and the diffuse idiopathic skeletal hyperostosis (DISH) spectrum. In this article, we show how imaging has resulted in an enthesis-centric model for different disease pathology compartmentalisation or a 'root and trunk' model for pathological process development. Whilst ankylosing spondylitis is predominantly characterised by early entheseal bony anchorage-related osteitis (root inflammation) and DISH is characterised by ligamentous soft-tissue ossification, ax-PsA is more heterogenous. Whilst ax-PsA may share an identical osteitis pattern to ax-SpA, a substantial proportion of ax-PsA cases have a soft tissue or tree trunk pathology that manifests as back pain with lack of osteitis but prominent ligamentous trunk ossification at later stages. We illustrate this using different imaging modalities to create a base for imaging research to elucidate this pattern of pathology.

Axial involvement in psoriatic arthritis: is it unique?

Axial involvement in psoriatic arthritis (PsA) has been a major feature of the disease since the original description by Wright and Moll. However, despite over 50 years of study, there is still no accepted definition of axial PsA, nor validated classification criteria. Numerous observational studies have described a phenotype of axial involvement that differs from classical ankylosing spondylitis (AS or axial spondyloarthritis) both clinically and radiographically, and in the frequency of the HLA-B27 antigen. These differences are important clinically, as axial PsA may be less prominent than AS, and in terms of treatment. This short review discusses these issues and offers some clarification for clinicians.

How Are We Addressing Axial Psoriatic Arthritis in Clinical Practice?

Psoriatic arthritis (PsA) is a chronic inflammatory disease affecting the musculoskeletal system, skin and nails. In addition to peripheral joints, inflammation of the spine and sacroiliac joints may occur. Yet, research into this axial phenotype has lagged behind partly because of the challenge in its clinical identification with a lack of specific clinical, molecular or imaging biomarkers. In the absence of a validated definition of what constitutes axial PsA (axPsA), guidelines for the management of axial involvement in PsA in clinical practice are scarce. On the basis of a literature review and their clinical expertise, a group of rheumatology experts provide their opinion to aid the diagnosis and management of axial PsA in clinical practice.

Focusing on ligamentous soft tissue inflammation for the future understanding of early axial psoriatic arthritis

Imaging has transformed the understanding of inflammatory and degenerative arthritis in both peripheral and axial disease. In axial inflammation, fat suppression magnetic resonance imaging (MRI) has unravelled the role of sub-fibrocartilaginous osteitis in axial spondyloarthritis and the role of peri-entheseal vertebral body osteitis and subsequent spinal new bone formation. Established or late-stage axial psoriatic arthritis (PsA) cases often exhibit impressive para-marginal or chunky syndesmophytosis on conventional X-ray that pathologically represents entheseal soft tissue ossification. However, the spinal entheseal soft tissue and contiguous ligamentous tissues are poorly visualized on MRI in subjects with early inflammatory back pain including those with axial PsA. In this article, we highlight the need for imaging modalities to discern the crucial soft tissue "ligamentous" component of axial PsA towards diagnosis, prognosis and therapy validation. We issue a clarion call to focus advanced imaging methodology on spinal ligamentous soft tissue that represents the last hidden backwater of PsA immunopathology that needs visualization to fully decipher axial PsA pathogenesis. This in combination with the existing ability to visualize ligamentous bony anchorage site osteitis is needed to define a gold standard test for axial PsA.

Exploring the unifying concept of spondyloarthritis: a latent class analysis of the REGISPONSER registry

OBJECTIVES

The aim of our study was to identify the potential distinct phenotypes within a broad SpA population.

METHODS

We conducted a cross-sectional study using the REGISPONSER registry, which has data from 31 specialist centres in Spain, including patients with SpA who have fulfilled the ESSG criteria. A latent class analysis (LCA) was performed to identify the latent classes underlying SpA according to a set of predefined clinical and radiographic features, independently of expert opinion.

RESULTS

In a population of 2319 SpA patients, a five-classes LCA model yielded the best fit. Classes named 'Axial with spine involvement' and 'Axial with isolated SI joint involvement' showed a primarily axial SpA phenotype defined by inflammatory back pain and high HLA-B27 prevalence. Patients in class 'Axial + peripheral' showed a similar distribution of manifest variables to previous classes but also had a higher likelihood of peripheral involvement (peripheral arthritis/dactylitis) and enthesitis, therefore representing a mixed (axial and peripheral) subtype. Classes 'Peripheral + psoriasis' and 'Axial + peripheral + psoriasis' were indicative of peripheral SpA (and/or PsA) with high likelihood of psoriasis, peripheral involvement, dactylitis, nail disease, and low HLA-B27 prevalence, while class 'Axial + peripheral + psoriasis' also exhibited increased probability of axial involvement both clinically and radiologically.

CONCLUSION

The identification of five latent classes in the REGISPONSER registry with significant overlap between axial and peripheral phenotypes is concordant with a unifying concept of SpA. Psoriasis and related features (nail disease and dactylitis) influenced the phenotype of both axial and peripheral manifestations.

Evaluation of the Possibility of Axial Psoriatic Arthritis Patients Meeting Classification Criteria for Axial Spondyloarthritis and Ankylosing Spondylitis

The objective of the study was to analyze whether axial psoriatic arthritis (axPsA) patients meet classification criteria for axial spondyloarthritis (axSpA) and ankylosing spondylitis (AS). A total of 104 patients (66 men and 38 women) with PsA according to CASPAR criteria were examined, all patients had back pain. Patients were evaluated for presence of inflammatory back pain (IBP) by ASAS criteria. Back pain not meeting the ASAS criteria was taken to be chronic back pain (chrBP). Patients underwent hands, feet and pelvis, cervical spine and lumbar spine X-rays. Erosions, osteolysis, and juxta-articular new bone formation were evaluated. Definite radiographic sacroiliitis (d-rSI) was defined as bilateral grade ≥ 2 or unilateral grade ≥ 3. Nineteen patients without d-rSI underwent sacroiliac joints MRI. Ninety-three patients underwent HLA B27 examination. The number of patients who met the criteria for axSpA (ASAS) and the modified New York (mNY) criteria for AS was determined. IBP was identified in 67 (64.4%) patients; chrBP, in 37 (35.6%) patients; 31 (29.8%) patient were of older age (over 40) at the onset of IBP/chrBP; 57 (58.8%) patients had d-rSI; 6 (31.6%) patients had MRI-SI; syndesmophytes were detected in 57 (58.8%) cases. Among 40 patients without d-rSI, 19 (47.5%) had syndesmophytes. In 38/97 (39.2%) patients d-rSI was detected along with syndesmophytes, while 19/97 (19.6%) patients had isolated d-rSI without spondylitis, and 19/97 (19.6%) patients had isolated syndesmophytes without d-rSI. HLA B27 was present in 28 (30.1%) cases. 51 (55.4%) patients met criteria for axSpA. Forty-one (44.6%) patients did not meet criteria for axSpA; however, 27 (65.9%) of them had syndesmophytes. Forty-eight (48.5%) PsA patients met mNY criteria for AS. Among these patients, a set of specific features was revealed: 18 (37.5%) had no IBP, 18 (37.5%) were of older age (over 40) at the onset of IBP/chrBP, 34 (70.8%) had dactylitis, 38 (79.2%) had erosive polyarthritis, 23 (48.8%) had juxta-articular new bone formation, 14 (30.2%) had osteolysis, 23 (48.9%) had "chunky" non-marginal syndesmophytes, and 40 (82.6%) had nail psoriasis; 28 (66.6%) patients were HLA-B27 negative. Forty-five percent of axPsA patients do not meet criteria for axSpA. Characteristic features have been identified to differentiate axPsA from AS.

The ATTRACT study: screening for the early identification of axial psoriatic arthritis in a cohort of Italian psoriatic patients

OBJECTIVE

There is growing interest in the early identification of patients with axial PsA (axPsA). We aimed to evaluate whether a dermatology-based screening strategy could help to identify axPsA patients.

METHODS

The dermatologist-centred screening (DCS) questionnaire was administrated by dermatologists to consecutive patients fulfilling the inclusion criteria [(i) age ≥18 years and (ii) clinical diagnosis of psoriasis made by a dermatologist] to identify patients eligible (affirmative answers 1-3c of the DCS) for rheumatological evaluation. Clinical, laboratory, genetic and imaging data were collected from all referred patients.

RESULTS

Among the 365 patients screened, 265 fulfilled the inclusion criteria and 124/265 (46.8%) were eligible for rheumatological referral. Diagnosis of axPsA, with or without peripheral PsA (pPsA), was made in 36/124 (29.0%) patients; pPsA without axial involvement was found in 21/124 (16.9%) patients. Back pain at screening was recorded in 174 (66%) patients, with 158 (60%) reporting a back pain duration longer than 3 months and 140 (53%) reporting back pain onset before the age of 45 years. Active inflammatory and/or structural post-inflammatory changes in the sacroiliac joints and/or spine were observed in all axPsA patients. Patients with PsA showed a numerically longer duration of back pain and higher CRP levels in comparison with patients with psoriasis without PsA.

CONCLUSION

The DCS tool proved to be a valuable screening strategy for detecting and characterizing patients with axPsA in a real-life cohort of psoriasis patients in a dermatological setting and helped to identify a substantial number of patients affected by undiagnosed pPsA.

Frequency and the effects of spondyloarthritis-spectrum disorders on the clinical course and management of Takayasu arteritis: an observational retrospective study

OBJECTIVES

Extravascular findings of Takayasu arteritis (TAK) often share features with the spondyloarthritis (SpA) spectrum of disorders. However, the characteristics of this overlap and its effect on the vascular manifestations of TAK are not fully known. Therefore, we aimed to investigate the frequency of SpA-related features in TAK patients.

MATERIAL AND METHODS

In this observational retrospective study, 350 patients with TAK classified according to ACR 1990 criteria, from 12 tertiary rheumatology clinics, were included and evaluated for the presence of axSpA, IBD, or psoriasis. Demographic, clinical features, angiographic involvement patterns, disease activity, and treatments of TAK patients with or without SpA were analyzed.

RESULTS

Mean age was 45.5 ± 13.6 years and mean follow-up period was 76.1 ± 65.9 months. Among 350 patients, 31 (8.8%) had at least one additional disease from the SpA spectrum, 8 had IBD, 8 had psoriasis, and 20 had features of axSpA. In the TAK-SpA group, TAK had significantly earlier disease onset, compared to TAK-without-SpA (p = 0.041). SpA-related symptoms generally preceded TAK symptoms. Biological treatments, mostly for active vasculitis, were higher in the TAK-SpA group (70.9%) compared to TAK-without-SpA (27.9%) (p < 0.001). Vascular involvements were similar in both.

CONCLUSION

Our study confirmed that diseases in the SpA spectrum are not rare in TAK. Vascular symptoms appeared earlier in such patients, and more aggressive therapy with biological agents was required in the TAK-SpA group, suggesting an association between TAK and SpA spectrum. Key Points • The pathogenesis of Takayasu arteritis is mediated by an MHC class I alelle (HLA-B*52), similar to spondyloarthritis-disorders. • Extravascular findings of Takayasu arteritis are in the spectrum of spondyloarthritis disease. • This frequent coexistence between Takayasu arteritis and spondyloarthritic disorders suggests a relationship rather than a coincidence.

Disease characteristics, pathogenesis, and treatment controversies of axial psoriatic arthritis

Axial psoriatic arthritis (axPsA) has considerable overlap with axial spondyloarthritis (axSpA) but has some unique features that sometimes preclude classification into axSpA. It has some clinical and radiographic differences compared to axSpA. Imaging typically shows asymmetric syndesmophytes, mainly in the cervical spine, with less frequent sacroiliitis. It more commonly presents later in life and is associated with less severe inflammatory back pain than axSpA. The interleukin (IL) IL-23/IL-17 axis is central to the pathogenesis of both diseases. However, the response to therapies targeting these cytokines has been different. IL-23 inhibitors are ineffective in axSpA but may be effective in psoriatic arthritis (PsA). Recent post hoc analyses of clinical trial data with IL-23 inhibitors in PsA have raised the possibility of their efficacy in axPsA and need evaluation in future clinical trials. Moreover, there is a need for classification criteria for axPsA and better tools to assess therapeutic response.

Predominant ligament-centric soft-tissue involvement differentiates axial psoriatic arthritis from ankylosing spondylitis

Since the original description of spondyloarthritis 50 years ago, results have demonstrated similarities and differences between ankylosing spondylitis (AS) and axial psoriatic arthritis (PsA). HLA-B27 gene carriage in axial inflammation is linked to peri-fibrocartilaginous sacroiliac joint osteitis, as well as to spinal peri-entheseal osteitis, which is often extensive and which provides a crucial anatomical and immunological differentiation between the AS and PsA phenotypes. Specifically, HLA-B27-related diffuse bone marrow oedema (histologically an osteitis) and bone marrow fatty corners detected via magnetic resonance imaging, as well as radiographic changes such as sacroiliitis, vertebral squaring, corner erosions and Romanus lesions, all indicate initial bone phenotypes in HLA-B27+ axial disease. However, in much of PsA with axial involvement, enthesitis primarily manifests in ligamentous soft tissue as 'ligamentitis', with characteristic lesions that include para-syndesmophytes and sacroiliac joint bony sparing. Like axial PsA, diffuse idiopathic skeletal hyperostosis phenotypes, which can be indistinguishable from PsA, exhibit a thoracic and cervical spinal ligamentous soft-tissue tropism, clinically manifesting as syndesmophytosis that is soft-tissue-centric, including paravertebral soft-tissue ossification and sacroiliac soft-ligamentous ossification instead of joint-cavity fusion. The enthesis bone and soft tissues have radically different immune cell and stromal compositions, which probably underpins differential responses to immunomodulatory therapy, especially IL-23 inhibition.

Management of psoriatic arthritis: a consensus opinion by expert rheumatologists

Background

Psoriatic arthritis (PsA) is a chronic inflammatory musculoskeletal disease involving several articular and extra-articular structures. Despite the important progresses recently made in all of the aspects of this disease, its management is still burdened by unresolved issues. The aim of this exercise was to provide a set of statements that may be helpful for the management of PsA.

Methods

A group of 38 Italian rheumatologists with recognized expertise in PsA selected and addressed the following four topics: "early PsA," "axial-PsA," "extra-articular manifestations and comorbidities," "therapeutic goals." Relevant articles from the literature (2016-2022) were selected by the experts based on a PubMed search. A number of statements for each topic were elaborated.

Results

Ninety-four articles were selected and evaluated, 68 out of the 1,114 yielded by the literature search and 26 added by the Authors. Each of the four topic was subdivided in themes as follows: transition from psoriasis to PsA, imaging vs. CASPAR criteria in early diagnosis, early treatment for "early PsA"; axial-PsA vs. axialspondyloarthritis, diagnosis, clinical evaluation, treatment, standard radiography vs. magnetic resonance imaging for "axial PsA"; influence of inflammatory bowel disease on the therapeutic choice, cardiovascular comorbidity, bone damage, risk of infection for "comorbidities and extra-articular manifestations"; target and tools, treat-to-target strategy, role of imaging for "therapeutic goals." The final document consisted of 49 statements.

Discussion

The final product of this exercise is a set of statements concerning the main issues of PsA management offering an expert opinion for some unmet needs of this complex disease.

Higher frequency but similar recurrence rate of uveitis episodes in axial spondylarthritis compared to psoriatic arthritis. A multicentre retrospective study

BACKGROUND/OBJECTIVE

Data on risk factors predicting uveitis development in spondyloarthritis (SpA) is scarce. Our aim was to examine associations between demographic, clinical and/or laboratory characteristics of SpA with the occurrence and the course of uveitis, including ocular damage and recurrence rate.

METHODS

Characteristics (at disease diagnosis and ever-present) from axSpA and Psoriatic arthritis (PsA) patients followed in 3 tertiary rheumatology-clinics were retrospectively recorded. Comparisons were made between patients with and without uveitis, as well as between those with uveitis-rate [episodes/year] above the median uveitis-rate in the whole cohort ("recurrent"-uveitis) and the remaining uveitis patients ("non-recurrent uveitis"). In multivariable models, age, gender and variables significantly different in univariate analyses were included.

RESULTS

264 axSpA and 369 PsA patients were enrolled. In axSpA, uveitis occurred in 11.7% and was associated with HLA-B27 (OR = 4.15, 95%CI 1.16-14.80, p = 0.028) and ever-present peripheral arthritis (OR = 3.05 (1.10-8.41, p = 0.031). In contrast, uveitis in PsA occurred only in 2.7% of patients and was associated with SpA family-history (OR = 6.35 (1.29-31.27), p = 0.023) axial disease at diagnosis (OR = 5.61 [1.01-28.69], p = 0.038) and disease duration (OR = 1.12 [1.04-1.21], p = 0.004). Median uveitis recurrence rate was comparable between axSpA and PsA (0.205 and 0.285 episodes/year, respectively). No associations were found between recurrent uveitis and demographic/clinical/laboratory characteristics. Ocular damage (e.g. synechiae) was seen in 16.1% of axSpA and 30% of PsA patients, all of them with recurrent uveitis.

CONCLUSION

Uveitis occurred more commonly in axSpA than in PsA patients, while uveitis recurrence rate was similar. Permanent ocular damage may occur more often in PsA than axSpA.

Upadacitinib effectiveness and factors associated with minimal disease activity achievement in patients with psoriatic arthritis: preliminary data of a real-life multicenter study

BACKGROUND

Upadacitinib (UPA) is a selective JAK inhibitor recently approved for the treatment of psoriatic arthritis (PsA). In this post-approval study, we aimed to evaluate the effectiveness and safety of UPA over 24 weeks and identify clinical predictors of response, in a multicentric cohort of patients affected by PsA.

METHODS

One hundred and twenty-six patients with PsA treated with UPA were enrolled in 10 Italian centres. UPA effectiveness outcomes, such as the proportion of patients with MDA status, DAPSA remission, and low disease activity, ASDAS-CRP inactive and low disease activity, and change from baseline in DAPSA and ASDAS-CRP scores, were evaluated every 12 weeks until week 24. The proportion of DAPSA minor, moderate, and major improvement, and ASDAS clinically important improvement (CII) and major improvement (MI) were considered as well. All treatment-related adverse events were collected during the observation period. Clinical predictors of MDA response at week 24 were evaluated through multivariate analysis.

RESULTS

At baseline, 124/126 (98%) and 54/126 (43%) patients showed peripheral and axial involvement, respectively; 110 (87%) patients were intolerant or resistant to biologic DMARDs.  At 24 weeks, MDA status, DAPSA remission, and ASDAS-CRP inactive disease were achieved in 47%, 23%, and 48% of patients, respectively. Minor, moderate, and major DAPSA improvement was observed in 67%, 39%, and 23%, respectively; while 65% and 35% achieved ASDAS-CRP CII and MI, respectively. The mean change from baseline was 15.9 ± 13.5 (p < 0.001) for DAPSA and 1.21 ± 0.97 (p < 0.001) for ASDAS-CRP. Thirteen patients (10%) discontinued UPA due to a lack of efficacy or non-serious adverse events. No serious adverse events were observed. Male gender (OR 2.54, 95% CI 1.03-6.25 p = 0.043), being naïve to biological DMARDs (OR 4.13, 95% CI 1.34-12.71, p = 0.013) and elevated baseline CRP (OR 2.49, 95% CI 1.02-6.12, p = 0.046) were associated with MDA response at week 24.

CONCLUSIONS

This is one of the first real-life studies supporting the effectiveness of UPA and its safety profile in PsA patients. Furthermore, the study identifies predictors of MDA response to UPA treatment at 6 months.

Identification of the first signs or symptoms in different spondyloarthritis subtypes and their association with HLA-B27: data from REGISPONSER and RESPONDIA registries

OBJECTIVE

To describe and analyse the initial symptoms attributable to patients with spondyloarthritis (SpA) and their association with HLA-B27 status.

METHODS

This was an observational, cross-sectional and multicentre study with patients who fulfilled the European Spondyloarthropathy Study Group criteria for SpA from the Registry of Spondyloarthritis of Spanish Rheumatology (REGISPONSER) and Ibero-American Registry of Spondyloarthropathies (RESPONDIA) united registries. Differences in the first sign(s) or symptom(s) were compared across diagnoses and between HLA-B27 status. The diagnostic delay between patients who start the disease with musculoskeletal manifestations (MMs) and extra-MMs (EMMs) was compared.

RESULTS

A total of 4067 patients were included (2208 from REGISPONSER and 1859 from RESPONDIA) (ankylosing spondylitis (AS): 68.3%, psoriatic arthritis (PsA): 19.9%, undifferentiated SpA: 11.8%). Overall, 3624 (89.1%) patients initiated the disease with MMs and 443 (10.9%) with EMMs. Low back pain (61.7%) and lower-limb arthritis (38.5%) were the most frequent initial symptoms. In AS patients, the absence of HLA-B27 seems to be related to an increase in the probability of starting the disease with cervical pain and peripheral manifestations. In PsA, the onset of arthritis and psoriasis was more prevalent in HLA-B27-negative patients, while initiation with axial manifestations was more predominant in HLA-B27-positive patients. The diagnostic delay was longer in patients with initial MMs than in those with EMMs (7.2 (34.8) vs 4.5 (7.6) years, respectively).

CONCLUSION

In this SpA population, MMs were the most prevalent initial symptoms, with differences across diagnoses and depending on the presence of the HLA-B27 antigen.

Spondyloarthropathies That Mimic Ankylosing Spondylitis: A Narrative Review

Ankylosing spondylitis is the most common type of seronegative inflammatory spondyloarthropathy often presenting with low back or neck pain, stiffness, kyphosis and fractures that are initially missed on presentation; however, there are other spondyloarthropathies that may present similarly making it a challenge to establish the correct diagnosis. Here, we will highlight the similarities and unique features of the epidemiology, pathophysiology, presentation, radiographic findings, and management of seronegative inflammatory and metabolic spondyloarthropathies as they affect the axial skeleton and mimic ankylosing spondylitis. Seronegative inflammatory spondyloarthropathies such as psoriatic arthritis, reactive arthritis, noninflammatory spondyloarthropathies such as diffuse idiopathic skeletal hyperostosis, and ochronotic arthritis resulting from alkaptonuria can affect the axial skeleton and present with symptoms similar those of ankylosing spondylitis. These similarities can create a challenge for providers as they attempt to identify a patient's condition. However, there are characteristic radiographic findings and laboratory tests that may help in the differential diagnosis. Axial presentations of seronegative inflammatory, non-inflammatory, and metabolic spondyloarthropathies occur more often than previously thought. Identification of their associated symptoms and radiographic findings are imperative to effectively diagnose and properly manage patients with these diseases.