Laboratory and imaging investigations for systemic disease associated with skin conditions
Which blood, urine and imaging tests to order for vasculitis, cutaneous lupus, dermatomyositis, scleroderma, sarcoidosis, erythema nodosum, neutrophilic dermatoses, porphyria, generalised itch and blistering disease; how to read ANA titres and patterns, ENA and myositis antibodies, complement and cryoglobulins, and the sampling errors that give false results.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Skin findings often lead to a systemic diagnosis. Order tests to answer specific questions: is there organ involvement, what is the cause, and is it safe to treat?
- Pattern recognition comes first; see cutaneous signs of systemic disease. Biopsy technique is in skin biopsy.
- Urinalysis is the cheapest test with the biggest pay-off: it finds glomerulonephritis in vasculitis and lupus.
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Sources
- Therapeutic Guidelines: Dermatology and RheumatologyAU/NZTherapeutic Guidelines Limited (eTG complete), current eTG edition, accessed November 2026 (topic version not verified)
- RCPA Manual: antinuclear antibodies, extractable nuclear antigens, myositis antibodies, cryoglobulins, porphyrinsAU/NZRoyal College of Pathologists of Australasia, online edition, accessed November 2026
- Oldroyd AGS et al. International guideline for idiopathic inflammatory myopathy-associated cancer screening: an IMACS initiative. Nat Rev Rheumatol 2023;19:805-17Nature Reviews Rheumatology, 2023 (author correction 2024)
- Aringer M et al. 2019 European League Against Rheumatism/American College of Rheumatology classification criteria for systemic lupus erythematosus. Arthritis Rheumatol 2019;71:1400-12EULAR/ACR, 2019
- Tan EM et al. Range of antinuclear antibodies in healthy individuals. Arthritis Rheum 1997;40:1601-11Arthritis and Rheumatism, 1997
- Crouser ED et al. Diagnosis and detection of sarcoidosis. An official American Thoracic Society clinical practice guideline. Am J Respir Crit Care Med 2020;201:e26-51American Thoracic Society, 2020
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy