Connective Tissue Diseases (CTDs)

Systemic Lupus Erythematosus (SLE)

• Skin: Malar rash (typically spares nasolabial folds), photosensitivity

• Joints: Non-erosive arthritis (common in hands, knees)

• Renal: Proteinuria, lupus nephritis (may present with oedema, haematuria)

• Haematology: Anaemia, leukopenia, thrombocytopenia

• Serology: Positive ANA, anti-dsDNA, anti-Smith antibodies (high specificity); other markers can include low C3/C4

Systemic Sclerosis (Scleroderma)

• Skin: Progressive thickening, reduced elasticity; may have pitting at fingertips

  • Localised forms: Morphea, linear scleroderma (often confined to skin/subcutaneous tissue)

  • Systemic forms: Diffuse or limited (CREST syndrome)

• CREST Syndrome (Limited Cutaneous Scleroderma):

  • Calcinosis

  • Raynaud’s phenomenon

  • Oesophageal dysmotility

  • Sclerodactyly

  • Telangiectasia

• Serology:

  • Anti-centromere antibodies (associated with limited cutaneous scleroderma)

  • Anti-Scl-70 (anti-topoisomerase I) in diffuse disease

Sjögren’s Syndrome

• Glands: Dry eyes (keratoconjunctivitis sicca), dry mouth (xerostomia), parotid gland swelling

• Other Features: Arthralgia, fatigue, occasionally vasculitis or interstitial lung disease

• Complications: Increased risk of non-Hodgkin lymphoma

• Serology: Anti-Ro (SSA) and anti-La (SSB) antibodies; can have rheumatoid factor positivity

Polymyositis

• Muscle: Symmetrical proximal weakness (difficulty climbing stairs, lifting arms overhead)

• Associated Condition: Dermatomyositis (skin findings: Gottron papules over knuckles, heliotrope rash on eyelids)

• Labs: Elevated muscle enzymes (CK, aldolase, AST, ALT)

• Serology: Anti-Jo-1 antibody (seen in antisynthetase syndrome), others include anti-Mi-2

Additional Context

• Mixed CTD: Overlapping features of SLE, systemic sclerosis, and polymyositis with anti-U1 RNP antibodies

• Raynaud’s Phenomenon: Often present across various CTDs and may precede other symptoms