Dermatomyositis is an autoimmune condition characterised by myositis and characteristic skin changes. It may be a paraneoplastic phenomenon – commonly from lung, pancreatic, ovarian, or bowel malignancy.

Polymyositis is an autoimmune-mediated inflammation of striated muscle. It is characterised by a slow onset of progressive symmetrical proximal muscle weakness, and myalgia +/- arthralgia.

Different antibodies have different disease associations Antibody Disease association Nota bene Rheumatoid factor (RF) Positive in Sjögren syndrome (≤ 100%), Felty’s syndrome (≤ 100%), rheumatoid arthritis (70%), mixed connective tissue disease (50%), hepatitis and infective endocarditis (<50%), SLE (≤ 40%),…

Ankylosing spondylitis is an autoimmune seronegative spondyloarthopathy that affects the axial skeleton and joints (shoulder and hip). It is HLA-B27 positive. It is more predominant in young men (under the age of 40), with a male-to-female ratio of 4:1.

Enteric arthritis is a seronegative spondyloarthopathy associated with gastrointestinal disease. Joint symptoms may precede bowel disease, occur simultaneously, or develop years later.

Reactive arthritis is a rare systemic inflammatory condition that follows gastrointestinal and urogenital infections. It presents with the triad of urethritis, conjunctivitis, and arthritis – “Can’t pee, can’t see, can’t climb a tree”. It is part of the seronegative spondyloarthropathies.

Psoriatic arthropathy is a chronic inflammatory, seronegative spondyloarthopathy associated with psoriasis. It occurs in 10-40% of patients with psoriasis and can present without skin changes. Classification of Psoriatic Arthropathy Classification Description Oligoarthritis Affects less than 5 joints and tends to be asymmetrical. This…

Seronegative spondyloarthropathies (spondyloarthritides) are a group of chronic inflammatory conditions that commonly affect the axial skeleton, lack rheumatoid factor and anti-CCP antibodies. Diagnostic hallmarks of Seronegative spondyloarthropathies Feature Description Seronegativity Rheumatoid factor and anti-CCP negative Genetic association HLA-B27 association –…