Lymphoedema Evidence Library › Topics › Definitions and staging
Definitions and staging
Definitions, classification and staging
20 sources
Evidence in one minute
- Lymphoedema is low-output failure of lymph transport — primary (developmental) or secondary (surgery, radiotherapy, infection, filariasis, trauma); ~85% worldwide is secondary. High-output oedema (heart, liver, kidney, venous) is different, but long-standing high-output states can damage lymphatics and become mixed. Executive Committee of the International Society of Lymphology 2023
- Chronic oedema = swelling present ≥3 months; Wounds Canada 2025 treats all chronic oedema as lymphatic dysfunction — a deliberately broad definition. Keast 2025 · Charles 2013
- ISL stages: 0 latent (measurable only — BIS, TDC); I pitting, reduces with elevation; II fat and fibrosis, elevation rarely helps; III lymphostatic elephantiasis. A limb can carry more than one stage.
- Severity (unilateral): minimal/mild >5 to <20% excess volume; moderate 20–40%; severe >40%.
- Primary lymphoedema by age: congenital (<2 y), praecox (2–35 y), tarda (>35 y); familial forms warrant genetic testing (FOXC2, FLT4/VEGFR-3, VEGFC, SOX18, GJC2, PIEZO1, GATA2 and others).
- Lipoedema is not lymphoedema (fat disorder sparing hands and feet; Stemmer negative) but can progress to lipo-lymphoedema. Lipoedema
- SA usage: the LAOSA statement adopts ISL staging and the same primary/secondary split. Davey 2018
Certainty: definitions and staging are consensus (LoE 5), internationally agreed; severity bands are conventional rather than outcome-validated.
Burden figures (all estimates)
- >200 million worldwide; 1–2% of population quoted by SA authors (extrapolated, no SA data) → 530 000–1.06 million South Africans. Davey 2014
- Primary lymphoedema ~1 in 6000 births (Keast; other sources 1.15 per 100 000 under 20 — figures conflict); lymphatic filariasis >120 million infected. Keast’s “80% of the morbidly obese have lymphoedema” is uncited (revised 2026-10-09). Keast 2014
- Chronic oedema 1.33 per 1000, ~1 per 200 over 65 (Moffatt 2003, via Charles 2013).
Gaps
No South African prevalence study exists in this library.
Update 2026-10-09 — open-access batch 10 (reviews)
- Animal models (Hsu 2022): most rodent models resolve spontaneously within weeks, unlike human lymphoedema — caution with animal-based treatment claims. Hsu 2022
How the evidence points
| High | Mod. | Low | V. low | None | |
|---|---|---|---|---|---|
| Positive | 0 | 0 | 0 | 0 | 0 |
| Null or negative | 0 | 0 | 0 | 0 | 0 |
Sources on this page with a comparison, by the result of their primary outcome and the GRADE certainty of their main finding (Mod. = Moderate, V. low = Very low, None = not graded). Context sources are not counted. How direction is decided.
All 20 sources
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