Features Some 40 % of patients with psoriasis or PsA have a family history of these conditions in first-degree relatives . 9
As with psoriasis , T-cells appear to play a central role in PsA , although the mechanisms are not fully understood .
Enthesitis is a feature of PsA ; i . e ., inflammation of the entheses ( the sites where ligaments or tendons insert into bones ). This can affect the soles of feet ( i . e ., plantar fascia ), the Achilles tendons , and the ribs , spine and pelvis . 11
Dactylitis or ‘ sausage digits ’ ( inflammation that affects an entire finger or toe ) is also a characteristic feature of PsA . It commonly involves a few fingers or toes but is often not symmetrical . 11
Axial involvement ( i . e ., spondylitis ) can also be a feature of PsA leading to inflammation and stiffness especially in the neck , but also lower back or sacroiliac region . 11
Other auto-immune rheumatological diseases Juvenile idiopathic arthritis Juvenile idiopathic arthritis ( JIA ) is a heterogeneous group of diseases and is different from adult RA . 5 It is a chronic rheumatological disease of childhood , associated in some patients with progressive joint destruction and serious systemic manifestations . It appears to be triggered by complex immunological changes .
Distinct sub-classifications of JIA have been defined . 12 However in 2019 , the verification process for a new classification system was started . 13
Incidence / prevalence JIA is the most common paediatric rheumatological disorder . 14 It affects more females than males (> 2:1 ) but the distribution and age of onset varies within the disease classification and
15 , 16 subtypes .
Clinical presentation , course , prognosis Chronic inflammation of the joints presents as synovitis and as a painful , red , swollen joint ( s ) with limited range of movement and , if the arthritis is prolonged , potential for joint deformities and growth disturbances . 17
There can be a significant time between onset of first symptom and diagnosis and there is also a risk of misdiagnosis , as JIA can closely resemble other conditions . 18 JIA-associated uveitis is one of the most common extraarticular manifestations of this condition , which is commonly associated with the presence of ANA .
Features The exact pathogenesis of JIA remains unclear , although it is widely thought to be a result of both genetic and environmental factors . 1 8 A specific genetic association is HLA-A2 , and which shows associations with early-onset disease . 18
A genetic component of JIA is thought to be significant as monozygotic twin concordance is between 25 % and 40 % and sibling concordance is 15 – 30-times above the prevalence in the general population . 19
Possible environmental stimuli include infection , childhood
18 , 19 antibiotics , and stress and trauma .
Systemic lupus erythematosus Systemic lupus erythematosus ( SLE ) is a potentially fatal autoimmune disease that can affect multiple organs . 20 It can have a significant impact on a patient ’ s quality of life and is associated with higher mortality rates than the general population . Diagnosis is challenging as it is a heterogenous disease with diverse clinical features ( including renal , neurological and cutaneous manifestations ; see Dermatology spotlight in this handbook ). It typically affects women of childbearing age . 20
Development of SLE is influenced by both genetic ( concordance rate in monozygotic twins is 25 %) and environmental factors , including exposure to UV light , smoking , infection with Epstein Barr virus and certain drugs ( for example , procainamide , carbamazepine and hydralazine amongst others ). 20
ANA , anti-Sm , anti-double-stranded antibodies are important biomarkers for this condition . Defects in the complement component C1Q and C4 genes are observed in SLE , together with IFN regulatory factor 5 mutations . 20
Annual incidence rates in the US are 2 – 7.6 / 100,000 whereas incidence rates and prevalence in Europe are between 1 and 4.9 / 100,000 and 28 and 97 / 100,000 , respectively . 20
Sjogren ’ s syndrome Sjögren ’ s syndrome is a chronic autoimmune disease associated with dry mouth and eyes resulting from immune-mediated damage to salivary and lachrymal glands . It is a systemic disease and can affect the secretary epithelium in a number of organs . Joint pain and fatigue are the other hallmark features . 21 It is estimated to affect 0.04 % of the European population . 21
The main complication of Sjögren ’ s syndrome is lymphoma and approximately 5 % of those will develop non-Hodgkin lymphoma . 21 Renal tubular acidosis is a recognised but rare complication .
There is a strong association with this condition and the presence of ANA , anti-SSa and anti-SSb antibodies .
Systemic sclerosis Systemic sclerosis is a systemic autoimmune disease of unknown origin . It is characterised by vascular changes and excessive deposition of collagen in skin and multiple internal organs leading to thickening and tightening of the skin and inflammation and scarring of other organs . 22 Symptoms affecting many parts of the body may be evident .
The estimated prevalence is 276 cases per million population (~ 0.03 %) and it is 4 – 9-times more common in women .
Raynaud ’ s phenomenon is typically the first symptom of systemic sclerosis followed by stiffening and tightening of the skin of the hands ( sclerodactyly ), face and feet , joint or muscle pain and stiffness and digestive problems ( swallowing difficulties , heartburn ). 23 The two diagnostic types of localised or diffuse scleroderma have typical phenotypes and associated autoantibodies ( anti-centromere and anti-Scl70 , respectively )
Genetic risk factors play an important role in its development 22 but the relationship between these genetic markers and environmental factors has not been fully elucidated .
ANA , anti-Scl70 and anti-centromere antibodies are strongly associated with this condition . A proportion of people with systemic sclerosis ( 15 – 25 %) also have overlapping signs and symptoms of other connective tissue diseases including RA , Sjögren ’ s syndrome or SLE .
Systemic sclerosis is associated with the highest mortality amongst the systemic autoimmune diseases , the most frequent causes of mortality being pulmonary hypertension , pulmonary fibrosis ( i . e ., interstitial lung disease ) and scleroderma renal crisis . 22 hospitalpharmacyeurope . com | 13