Scope and Positioning
Who this is for: Haematology trainees, general medicine registrars, and clinicians managing adult patients with suspected or confirmed ITP in secondary care. This summary reflects UK practice and is aligned with ASH and NICE frameworks.
This guideline covers
- Diagnosis of primary ITP as a diagnosis of exclusion
- Clinical and laboratory approach to isolated thrombocytopenia
- Treatment decisions — including the critical question of when to treat versus observe
- First-line corticosteroid and IVIG strategies
- Second-line and subsequent therapy options available within NHS England
- Emergency management of severe or life-threatening bleeding in ITP
- Principles of platelet transfusion in ITP
This guideline does not cover
- Paediatric ITP — management differs significantly; see paediatric haematology guidance
- Secondary ITP (e.g., SLE-associated, drug-induced) — these are managed by treating the underlying cause
- ITP in pregnancy — specialist obstetric haematology input required
- Thrombocytopenia in the context of chemotherapy or bone marrow failure
This is an expert-synthesised guideline summary, not a de novo systematic review. Recommendations are derived from published international society guidelines (ASH, NICE) and supplemented by primary trial evidence identified through those source documents. A formal independent systematic search was not conducted. Evidence quality and recommendation strength are graded using a simplified GRADE approach: High / Moderate / Low / Very Low for quality of evidence; Strong / Conditional for recommendation strength. Good practice statements based on clinical consensus are noted explicitly where direct evidence is absent. Guideline sources are credibility-graded (A1–C) in the references section.
In adults with isolated thrombocytopenia, which investigations are required to diagnose primary ITP and exclude secondary causes?
In adults with newly diagnosed ITP, what platelet count and clinical thresholds should guide the decision to initiate treatment versus observe?
In adults with ITP requiring treatment, what is the optimal first-line agent — prednisolone, high-dose dexamethasone, or IVIG — and for how long?
In adults with relapsed, refractory, or steroid-dependent ITP, which second-line therapies (TPO-RAs, rituximab, splenectomy) produce the most durable response?
What is ITP?
Immune thrombocytopenia (ITP) is a primary haematological autoimmune disorder characterised by isolated thrombocytopenia — defined as a platelet count below 100 × 10⁹/L[5] — in the absence of any identifiable underlying cause. It is a diagnosis of exclusion; no single test confirms ITP. (Note: the threshold of <100 × 10⁹/L replaced the earlier <150 threshold following the 2009 IWG consensus standardisation.)
Classification by disease duration[5]
Pathophysiology
ITP is driven primarily by autoantibody-mediated platelet destruction — predominantly IgG autoantibodies directed against platelet surface glycoproteins (GPIIb/IIIa, GPIb/IX) — leading to accelerated platelet clearance by the reticuloendothelial system, principally in the spleen. T-cell-mediated direct destruction of megakaryocytes contributes to impaired platelet production in many patients.
Epidemiology
Annual incidence in adults is approximately 3–4 per 100,000.[1] In adults, there is a bimodal distribution: young women (20–40 years) and older adults of both sexes. Unlike childhood ITP, spontaneous remission in adults is less common and chronic disease is more frequent.[1]
When to Suspect ITP
ITP should be suspected when a patient presents with isolated thrombocytopenia and features of mucocutaneous bleeding, or when thrombocytopenia is found incidentally on a routine blood test.
Typical clinical features
- Petechiae and purpura — typically lower limbs; spontaneous or with minor trauma
- Easy bruising, disproportionate to the degree of trauma
- Mucosal bleeding — epistaxis, gum bleeding, menorrhagia in women
- Incidental finding: isolated low platelet count on FBC with no clinical bleeding
- Absence of splenomegaly — splenomegaly is atypical in primary ITP and should prompt search for secondary cause
- Intracranial haemorrhage — severe headache, focal neurology, reduced GCS in a thrombocytopenic patient
- Severe mucosal bleeding — haemoptysis, haematemesis, haematuria, retinal haemorrhage
- Platelet count < 10 × 10⁹/L with any wet purpura (bullous lesions in the mouth)
- Fever + thrombocytopenia + neurological features — consider TTP; do not start steroids until blood film reviewed
- Thrombocytopenia + new thrombosis — consider HIT or antiphospholipid syndrome
Initial Assessment
History
- Medication review: quinidine, trimethoprim-sulfamethoxazole, vancomycin, heparin, anti-epileptics, proton pump inhibitors — many drugs can cause thrombocytopenia; a thorough medication history is mandatory
- Recent infection: viral illness in preceding 4–6 weeks (including HIV, EBV, CMV, hepatitis C); recent vaccination
- Systemic symptoms: joint pain, skin rashes, photosensitivity (SLE); night sweats, weight loss, lymphadenopathy (lymphoproliferative disease)
- Alcohol intake: direct myelosuppression and liver disease are common causes of thrombocytopenia
- Personal and family history: prior thrombocytopenia, bleeding disorders, autoimmune disease
- Bleeding history: onset, sites, severity, and relationship to platelet count trajectory
Examination
- Distribution and type of bleeding lesions — petechiae, purpura, ecchymoses, wet purpura in mucous membranes
- Lymphadenopathy — if present, raises concern for lymphoproliferative disease or infection
- Splenomegaly or hepatomegaly — atypical for primary ITP; warrants further investigation
- Signs of systemic disease — malar rash (SLE), jaundice (liver disease, haemolysis), pallor (Evans syndrome)
Investigations and Diagnosis of Exclusion
There is no diagnostic test that confirms ITP. The diagnosis is made by excluding other causes of isolated thrombocytopenia. The blood film is the single most important investigation and must not be omitted.
First-Line Investigations
- FBC with differential — confirm isolated thrombocytopenia; normal WBC, Hb, and MCV support primary ITP
- Blood film (mandatory) — exclude: pseudothrombocytopenia (EDTA-induced platelet clumping), TTP/HUS (schistocytes), lymphoproliferative disease (atypical lymphocytes/blast cells), MDS (dysplastic changes); confirm platelet morphology
- Clotting screen (PT, APTT) — normal in ITP; abnormality suggests DIC or liver disease
- Renal function, LFTs, and bone profile — liver disease, renal impairment
- Immunoglobulins — hypogammaglobulinaemia may suggest underlying lymphoproliferative disease
- HIV and hepatitis C serology — both are treatable causes of thrombocytopenia that may mimic ITP
- Helicobacter pylori testing — UREA breath test or stool antigen; eradication may improve platelet count in some patients
- ANA and anti-dsDNA — to exclude SLE as a secondary cause
- Blood group (ABO/RhD) — required before IVIG or anti-D therapy
Second-Line / Selective Investigations
- Bone marrow biopsy: not routinely required in typical primary ITP in patients under 60 with no atypical features; indicated before splenectomy, in patients ≥60 years, or where MDS/lymphoma cannot be excluded from peripheral film alone
- Direct antiglobulin test (DAT): if haemolysis suspected — to exclude Evans syndrome (autoimmune haemolytic anaemia + ITP)
- Antiphospholipid antibodies: if concurrent thrombosis or recurrent pregnancy loss — particularly relevant in women of childbearing age
- Platelet antibody testing: not recommended for routine diagnosis due to poor sensitivity and specificity[1]
- EBV, CMV serology: in younger patients with acute presentation and recent viral illness
Important Differentials — Not to Miss
The following conditions can present with isolated or predominant thrombocytopenia. Some carry significant management implications and require different treatment pathways.
- Thrombotic thrombocytopenic purpura (TTP): microangiopathic haemolytic anaemia + thrombocytopenia + neurological/renal features. Schistocytes on blood film. Do NOT treat with steroids alone — requires urgent plasma exchange and haematology input
- Heparin-induced thrombocytopenia (HIT): thrombocytopenia + new thrombosis in a heparinised patient. Requires immediate heparin cessation and alternative anticoagulation
Important Non-Emergency Differentials
- Pseudothrombocytopenia: EDTA-induced in vitro platelet clumping — check blood film; repeat FBC in citrate or heparin tube; no treatment required
- Drug-induced thrombocytopenia (DITP): many drugs implicated; review medication list thoroughly; usually resolves after drug withdrawal
- Systemic lupus erythematosus (SLE): check ANA, anti-dsDNA, complement levels; thrombocytopenia may be the presenting feature
- Antiphospholipid syndrome (APS): thrombocytopenia in context of VTE or recurrent pregnancy loss; check anticardiolipin, anti-beta-2-glycoprotein I, lupus anticoagulant
- Evans syndrome: autoimmune haemolytic anaemia + ITP; check DAT, reticulocyte count, LDH, and bilirubin
- Lymphoproliferative disease: CLL, lymphoma — blood film, lymph node examination, CT staging if clinical suspicion
- Myelodysplastic syndrome (MDS): particularly in older patients; bone marrow biopsy required to confirm
- HIV-associated thrombocytopenia: can mimic primary ITP; check HIV serology in all patients unless clearly excluded
- Hepatitis C-associated thrombocytopenia: treatable cause; direct-acting antivirals may restore platelet count
- Alcohol-related thrombocytopenia: direct marrow suppression and hypersplenism; often recovers with abstinence
When to Treat vs When to Observe
The decision to treat ITP is based on bleeding severity and clinical context, not platelet count alone. A patient with a platelet count of 15 × 10⁹/L who is asymptomatic may not require immediate treatment, while a patient with count 50 × 10⁹/L and significant mucosal bleeding does.
For adults with newly diagnosed ITP and a platelet count ≥ 30 × 10⁹/L who are not bleeding, the ASH guideline panel suggests observation over treatment. Many patients with counts in this range do not progress and do not require pharmacological intervention at diagnosis.
ITP Management Algorithm
Visual decision pathway from presentation through first-line and second-line treatment. Based on ASH 2019 framework.[1] Scroll horizontally on smaller screens.
Exclude: pseudothrombocytopenia · TTP (schistocytes) · MDS · lymphoproliferative disease
FBC · film · HIV · HCV · H.pylori · ANA · clotting · LFTs · renal · immunoglobulins
Mucosal · wet purpura · menorrhagia · GI · intracranial
Prednisolone ± IVIG
Tranexamic acid for mucosal
FBC 1–2 weeks
Bleeding education
Age · lifestyle · comorbidities
Treat if high-risk lifestyle
ICH · severe GI · haemoptysis
Haematology on-call immediately · Tranexamic acid 1 g TDS · ICH: neurosurgery + ICU
Dexamethasone: 40 mg/day × 4 days. Up to 3 cycles.
Plt rises within 24–48 h; transient (2–4 wks)
Use: bleeding + upcoming surgery + steroid failure
Avatrombopag (oral OD) — NICE TA853 (Dec 2022)
First-choice second-line agents in UK practice
Splenectomy: 60–70% long-term response; defer ≥12 months; pre-op vaccines essential
First-Line Treatment
First-line treatment aims to raise the platelet count to a safe level and control bleeding symptoms. Corticosteroids are the standard first-line agent. IVIG is added when a rapid response is required.
Dose: 1 mg/kg/day (maximum 80 mg/day) for 2–4 weeks, then taper over 4–6 weeks based on response.
Response: Platelet count typically rises within 1–2 weeks in responding patients. Approximately 70–80% achieve an initial response, but durable remission without further treatment occurs in fewer than 30% of adults.[1]
Important — ASH 2019: Corticosteroid courses should not be prolonged beyond 6 weeks.[1] Avoid maintenance prednisolone at doses that cause systemic toxicity solely to maintain a platelet count.
Cautions: hyperglycaemia, hypertension, mood changes, insomnia, osteoporosis with prolonged use; prescribe bone protection and monitor blood glucose in at-risk patients.
Dose: 40 mg/day for 4 consecutive days. May be repeated as up to 3 cycles at 14–28-day intervals.
Response: Produces a faster initial platelet rise compared with prednisolone. Long-term remission rates are similar to prednisolone at 6–12 months. May be preferred when a rapid response is needed or to avoid prolonged steroid courses.
Cautions: same as prednisolone. Blood glucose monitoring essential, particularly in patients with diabetes. Consider gastroprotection.
Dose: 1 g/kg as a single infusion; may be repeated after 24 hours if response is inadequate. Total dose of 2 g/kg is an alternative regimen given over 2 days.
Response: Rapid — platelet count typically rises within 24–48 hours. Effect is transient (2–4 weeks) but valuable as a bridge to longer-term treatment or in preparation for surgery/procedures.
Indications for IVIG: active significant bleeding regardless of platelet count; urgent surgery or invasive procedure requiring rapid platelet elevation; failure to respond to initial corticosteroids with ongoing bleeding.
Cautions: infusion reactions (headache, fever, chills); renal impairment (sucrose-containing formulations); haemolysis in patients with blood group A or B (rare); check IgA levels before administration if primary immunodeficiency suspected — IgA-deficient patients are at risk of anaphylaxis with IgA-containing IVIG.
All newly diagnosed ITP patients should be tested for H. pylori (urea breath test or stool antigen). In H. pylori-positive patients, eradication therapy (standard triple therapy per local formulary) is recommended.
A proportion of H. pylori-positive ITP patients will experience a sustained platelet count rise following successful eradication. This is a low-risk, low-cost intervention with potential benefit. Platelet response may take several months after eradication to become apparent.
Second-Line and Subsequent Treatment
Second-line therapy is considered in patients with persistent or chronic ITP who have relapsed after first-line treatment, remain dependent on corticosteroids at an unacceptable dose, or have chronic disease with insufficient platelet count and/or symptoms.
The choice of second-line agent should be guided by patient preference, comorbidities, fertility considerations, access (NICE approval), and local haematology expertise.
TPO receptor agonist (TPO-RA). Weekly subcutaneous injection. Stimulates platelet production by activating the thrombopoietin receptor on megakaryocytes. NICE-approved for adults with chronic ITP refractory to standard active treatments and rescue therapies, or those with severe disease and a high bleeding risk requiring frequent rescue therapy.[3] Response rate approximately 79–88%.[3] Does not induce disease remission — relapse on discontinuation is common.
Oral TPO receptor agonist. NICE-approved (December 2022) for adults with primary chronic ITP refractory to other treatments, including corticosteroids and immunoglobulins, subject to the commercial arrangement.[4] Once-daily oral dosing. Clinical trial evidence shows superior platelet response versus placebo.[4] May be as effective as other TPO-RAs; comparative trial data are currently indirect.
Anti-CD20 monoclonal antibody. Used in UK practice for persistent and chronic ITP refractory to first-line therapy. Not specifically NICE-approved for ITP — NICE evidence review notes limitations in the evidence base and recommends measured use. Typical regimen: 375 mg/m² weekly × 4 doses or low-dose 100 mg × 4 weekly doses. Approximately 60% initial response; durable 5-year remission in around 20%.[1,2] Risk of delayed-onset hypogammaglobulinaemia and infection.
Historically the most durable second-line option: 60–70% long-term complete response.[1] Now generally deferred until at least 12 months after diagnosis given availability of TPO-RAs. Requires pre-operative vaccination against encapsulated organisms (pneumococcal, Hib, meningococcal ACWY and B, influenza) ≥ 2 weeks before surgery. Lifelong penicillin prophylaxis and annual influenza vaccination post-splenectomy. Bone marrow biopsy required before proceeding.
Azathioprine, mycophenolate mofetil, ciclosporin, and danazol have been used in refractory ITP. Evidence is limited to small observational series. These agents are generally reserved for cases where other options have failed or are contraindicated, under specialist haematology guidance.
Emergency Management — Severe Bleeding
- Contact haematology on-call immediately — do not manage in isolation
- Initiate IV methylprednisolone 1 g/day for 3 days (or equivalent high-dose IV dexamethasone)
- Give IVIG 1 g/kg — may repeat after 24 hours if inadequate initial response
- Platelet transfusion in high doses (see Section 11) — combine with IVIG to prolong platelet survival
- Tranexamic acid 1 g three times daily — for mucosal, oral, or menstrual bleeding
- For intracranial haemorrhage: neurosurgery and intensive care involvement; consider emergency splenectomy in refractory cases
The goal in severe ITP bleeding is to achieve a rapid, temporary rise in platelet count sufficient to control haemorrhage. The combination of high-dose corticosteroids + IVIG + platelet transfusion provides the fastest achievable response. No single therapy alone is adequate in a life-threatening emergency.
Recombinant Factor VIIa has been used anecdotally in refractory life-threatening ITP bleeding but is not supported by controlled trial evidence and should be considered only as a last resort with haematology and haemostasis specialist input.
Platelet Transfusion Principles in ITP
Unlike most other causes of thrombocytopenia, transfused platelets in ITP are subject to the same autoimmune destruction as endogenous platelets. Transfused platelets have a very short half-life (minutes to hours in active ITP) and will not sustainably raise the platelet count. Platelet transfusion is therefore reserved for specific clinical indications — not used prophylactically for a low count alone.
Appropriate Indications for Platelet Transfusion in ITP
- Active severe or life-threatening bleeding — irrespective of platelet count
- Urgent surgical or invasive procedure where haemostasis is critical and platelet count is inadequate
- As a bridge while waiting for IVIG or corticosteroids to take effect in a bleeding patient
Practical Guidance
- Administer at higher than standard doses — at least 2 adult therapeutic doses (equivalent to at least 2 pools of random donor platelets or 2 apheresis units)
- Give simultaneously with IVIG if possible — IVIG temporarily reduces the rate of platelet destruction and prolongs the survival of transfused platelets
- Do not transfuse to a specific platelet count threshold in the absence of bleeding — the indication is clinical haemorrhage, not the count itself
- Repeat transfusions may be required at short intervals in severe bleeding — reassess frequently
Clinical Pearls and Pitfalls
- Missing pseudothrombocytopenia — always review the blood film before initiating any treatment; platelet clumping in EDTA is a benign cause of spurious thrombocytopenia
- Starting corticosteroids before excluding TTP — check blood film for schistocytes; TTP is a haematological emergency requiring plasma exchange, not steroids alone
- Treating newly diagnosed ITP with platelet count ≥30 and no bleeding — ASH 2019 supports observation[1]; unnecessary treatment exposes patients to steroid toxicity
- Prolonged corticosteroid use beyond 6 weeks — ASH 2019 recommends against this[1]; if a patient requires prolonged steroids, second-line therapy should be planned
- Routine platelet transfusion for isolated thrombocytopenia without bleeding — transfused platelets will be rapidly destroyed; not indicated without active haemorrhage
- Not checking HIV and HCV — both are treatable causes that may masquerade as primary ITP; antiviral therapy can restore the platelet count
- Not testing for H. pylori — a low-risk, low-cost test with potential treatment benefit; should be performed in all newly diagnosed patients
- ITP in pregnancy requires specialist obstetric haematology management — avoid prolonged steroids; IVIG is the preferred acute treatment; neonatal thrombocytopenia may occur and requires planning
- Bone marrow biopsy is not routinely required in typical primary ITP in patients under 60 with a normal blood film; it should be performed before splenectomy or if MDS or lymphoma cannot be excluded
- TPO receptor agonists do not induce immune remission — relapse after discontinuation is the rule rather than the exception; patients should be counselled about this before starting
- After splenectomy: lifelong penicillin V 250 mg twice daily prophylaxis; annual influenza vaccination; pneumococcal vaccine every 5 years; patient-held emergency information card
- Dexamethasone produces a faster initial response than prednisolone but long-term remission rates at 6–12 months are similar; use dexamethasone when a rapid response is desirable or when a short course is preferred
- The platelet count in ITP does not always correlate with bleeding risk — patients with chronic stable ITP often bleed less than those with acute-onset thrombocytopenia at the same count, due to younger, more haemostatically active platelets in ITP
Audit Standards and Quality Indicators
The following measurable standards support clinical audit, quality improvement, and local governance review. They are aligned with recommendations made in the ASH 2019 guideline and NICE technology appraisals for ITP.
| # | Audit Standard / Quality Indicator | Data Source | Target |
|---|---|---|---|
| 1 | New thrombocytopenia: blood film reviewed at diagnosis | Haematology lab / clinical record | 100% |
| 2 | ITP diagnosis documented as diagnosis of exclusion, with secondary causes excluded | Clinic letter / discharge summary | 100% |
| 3 | H. pylori testing performed in all newly diagnosed ITP patients | Microbiology / endoscopy records | ≥ 90% |
| 4 | Corticosteroid courses not extended beyond 6 weeks without documented clinical justification | Prescribing records / clinic letters | ≥ 95% |
| 5 | Platelet count response documented at 4 weeks following initiation of first-line treatment | Blood count results / clinic correspondence | ≥ 90% |
| 6 | Pre-splenectomy vaccination administered ≥ 2 weeks prior to surgery | Immunisation records / surgical notes | 100% |
| 7 | Patients referred to specialist haematology centre for refractory or complex ITP | Referral records | ≥ 90% |
Limitations and Guideline Update Plan
- Not a systematic review: This is a synthesised summary of published society guidelines, not a de novo systematic review. Independent literature searches were not conducted for individual clinical questions.
- Evidence gaps: Several ITP recommendations (particularly around long-term sequencing of second-line agents) are based on limited RCT evidence; indirect comparisons and observational data inform these areas.
- Generalisability: This summary reflects NHS England practice aligned with NICE approvals. Formulary access, availability, and local protocols differ internationally.
- Population exclusions: Paediatric ITP, secondary ITP, ITP in pregnancy, and ITP in bone marrow failure states are outside scope and require specialist input.
- Approved indications may change: NICE technology appraisals are subject to update; always verify current approval status and commercial arrangements for TPO-RAs.
Update Plan
This guideline summary will be reviewed when any of the following occur: (1) publication of a major updated ASH or BSH ITP guideline; (2) new NICE technology appraisal or guideline relevant to adult ITP; (3) publication of a landmark RCT altering current recommendations. In the absence of these triggers, a scheduled review will be undertaken no later than April 2028.
Guideline Basis
There is currently no single NICE clinical guideline covering all aspects of adult ITP management. This summary is anchored in the ASH 2019 guideline framework as the most comprehensive adult ITP guideline available, supplemented by NICE technology appraisals for specific NHS-approved agents and the 2009 International Working Group consensus for core definitions and classification.
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[1]American Society of Hematology 2019 guidelines for immune thrombocytopenia A1 — Society GuidelineNeunert C, Terrell DR, Arnold DM, et al. Blood Advances 2019;3(23):3829–3866. GRADE-based systematic review and evidence-to-decision framework. Available at hematology.org/guidelines
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[2]American Society of Hematology 2022 updated review — immune thrombocytopenia A1 — Society Guideline UpdateNeunert C, et al. Blood Advances 2024;8(13):3578–3594. Available at hematology.org/guidelines
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[3]Romiplostim for the treatment of chronic immune thrombocytopenia A1 — NICE Technology AppraisalNICE Technology Appraisal TA221. Published April 2011, updated October 2018. Available at nice.org.uk/guidance/ta221
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[4]Avatrombopag for treating primary chronic immune thrombocytopenia A1 — NICE Technology AppraisalNICE Technology Appraisal TA853. Published December 2022. Subject to commercial arrangement. Available at nice.org.uk/guidance/ta853
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[5]Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from an international working group A2 — Peer-reviewed consensusRodeghiero F, Stasi R, Gernsheimer T, et al. Blood 2009;113(11):2386–2393. Primary source for the <100 × 10⁹/L diagnostic threshold and the three-phase duration classification (newly diagnosed / persistent / chronic).
Versioning and Disclaimer
This guideline summary supports clinical decision-making and is intended for educational use by healthcare professionals. It does not replace individual clinical judgement, the full published ASH and NICE guidelines, local institutional protocols, or specialist haematology consultation. No single guideline covers all aspects of adult ITP management; clinicians should refer to the primary guideline sources listed above for complete recommendations. See the Clinical Governance page for full terms of use.