Paeds · paediatric-dermatology
Petechiae, purpura and vasculitic rashes
Also known as Petechiae · Purpura · Non-blanching rash · Immune thrombocytopenia · ITP · IgA vasculitis · Henoch-Schönlein purpura · Purpura fulminans · Meningococcaemia · Disseminated intravascular coagulation
Fellowship topic on the non-blanching rash in children — petechiae, purpura and vasculitic eruptions — framed as a triage problem. The first split is sick versus well: a febrile, toxic child with a rapidly evolving purpuric rash is meningococcal sepsis or purpura fulminans until proven otherwise and needs immediate antibiotics and resuscitation, while a well child with isolated petechiae and a normal examination is most likely immune thrombocytopenia (ITP). Cover the glass-test confirmation of non-blanching, the ISTH disseminated intravascular coagulation score and purpura fulminans, IgA vasculitis (Henoch-Schönlein purpura) with its palpable dependent purpura and mandatory renal follow-up, the haemolytic uraemic syndrome, leukaemia presenting as pancytopenia with blasts rather than isolated thrombocytopenia, and the safeguarding assessment of bruising using the TEN-4 FACES pattern. Diagnostic and triage focus throughout, cross-linking the dedicated sepsis, rash-approach and systemic-disease topics rather than duplicating their full protocols.
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Target exams
Red flags
- A febrile, ill-looking child with a rapidly spreading petechial or purpuric rash that does not blanch under a glass — treat as meningococcal septicaemia or purpura fulminans: airway-breathing-circulation, blood cultures, parenteral antibiotics within the first hour, and intensive care
- Purpura fulminans — large confluent purpuric patches with dusky grey-black centres and skin necrosis, usually with shock and disseminated intravascular coagulation — a dermatological and haematological emergency
- A well child with isolated petechiae or bruising but a normal full blood count has not been fully assessed — look at the film for blasts and confirm the platelets are the only abnormal line before labelling it ITP
- Bruising on the torso, ear or neck, facial bruising at the frenum or eyelid, or any bruise at all in a non-mobile infant (four months or younger) — apply the TEN-4 FACES pattern and consider non-accidental injury
- Palpable purpura on the lower limbs and buttocks with abdominal pain or joint swelling in a young child — IgA vasculitis; check the blood pressure and the urinalysis and arrange renal follow-up, because nephritis can develop over weeks
Life stages
Care settings
Clinical exam formats
Board mappings
- General Paediatrics and acute care: recognition of the non-blanching rash as a time-critical triage problem, the sick-versus-well first split, and the need for early antibiotics in the febrile purpuric child
- Haematology and dermatology: immune thrombocytopenia, IgA vasculitis, and the differentiation of isolated thrombocytopenia from marrow infiltration
- Renewed curriculum — acute and critical care: purpura fulminans, disseminated intravascular coagulation scoring, and resuscitation of the shocked purpuric child
- Child protection: application of the TEN-4 FACES bruising pattern and the safeguarding assessment
- General Paediatrics: triage and immediate management of the child with a non-blanching rash and the glass test
- Retrieval and critical care: early parenteral antibiotics, fluid resuscitation and transfer of the septic purpuric child
- Long Case / Structured discussion: a child presenting with petechiae — the differential from ITP through meningococcaemia to leukaemia, and the diagnostic workup
- Communication station: explaining a new diagnosis of ITP to a family, safety-netting for bleeding, and the safeguarding conversation around bruising
- Level 1 / 2 — Dermatology and haematology: the non-blanching rash, petechiae and purpura, and the recognition of the septic child
- Child protection and acute care: bruising patterns suggestive of non-accidental injury and the emergency management of purpura fulminans
- Foundation of Practice (FOP): the glass test, the causes of petechiae and purpura, and the sick-versus-well split
- Applied Knowledge in Practice (AKP): IgA vasculitis criteria, ITP definition and management, and the ISTH disseminated intravascular coagulation score
- History-taking and management planning: the well child with bruising and a low platelet count
- Communication: counselling the family of a child with newly diagnosed ITP and explaining safeguarding assessment
- General Pediatrics Content Outline — the non-blanching rash, meningococcaemia, ITP, Henoch-Schönlein purpura and child abuse bruising patterns
- Haematology and oncology: ITP and the differentiation from leukaemia; nephrology: IgA vasculitis nephritis
- Emergency and critical care: purpura fulminans and septic shock with a purpuric rash
- Patient Care: triage and resuscitation of the child with a non-blanching rash and early antibiotic therapy in suspected meningococcaemia
- Systems-Based Practice and Patient Safety: safeguarding referral for suspicious bruising and coordination across haematology, dermatology and child protection
- Medical Knowledge: pathophysiology of petechiae and purpura across ITP, vasculitis, disseminated intravascular coagulation and leukaemia
- Medical Expert: the differential and emergency triage of the non-blanching rash in children
- Health Advocate: recognition and reporting of non-accidental bruising using validated patterns
- Collaborator: coordination of care across emergency, haematology, nephrology and child-protection services
Two non-blanching rashes — the sick child versus the well child
Meningococcaemia / purpura fulminans (sick)
Immune thrombocytopenia (well)
A vasculitic purpura is palpable because inflammatory cells and fibrin raise the vessel wall. Remember the IgA vasculitis picture with PALPABLE: Palpable purpura on the lower limbs and buttocks (dependent areas), Abdominal pain, Limb (joint) pain or swelling, Proteinuria or haematuria on the urinalysis (renal involvement), Age under ten years typical, Blood pressure must be checked, and Look at the urinalysis and blood pressure for six to twelve months because nephritis can appear late. Palpable purpura that does not blanch in dependent areas is the clinical signature, and the kidney is the organ that decides the long-term outcome. [5] [6]
Overview & Definition
Picture an eighteen-month-old brought in with a fever and a handful of tiny red spots that did not fade when her mother pressed a glass against them. Within two hours the spots have become dark purple patches spreading up her legs, her peripheries are cold, and she is grunting. This is the scenario that petechiae and purpura exist to make you think about, because the difference between a five-minute and a one-hour antibiotic is the difference between life and death in meningococcal disease. The clinician's job is to run the sick-versus-well split in the first minute, confirm the rash is genuinely non-blanching, and then move down a short, fast differential. [8]
Petechiae are tiny pinpoint haemorrhages under about two millimetres, purpura are larger flat bruises from a few millimetres to roughly a centimetre, and ecchymoses are larger still. All three represent blood outside the vessel lumen, which is why they do not blanch when you press them with a glass — the so-called glass test or tumbler test. Their causes span platelet problems (too few or dysfunctional), vessel-wall problems (vasculitis, infection, trauma) and coagulation problems, and the art is to read the child's wellness, the rash morphology and the tempo together rather than to chase a single diagnosis. [8]
The triage frame has three layers. The first is how sick is the child — fever, toxicity, shock and rapid progression mark the emergencies. The second is what does the rash look like — petechial versus purpuric, flat versus palpable, dependent versus generalised, necrotic versus fresh. The third is the blood count and film — isolated thrombocytopenia points one way, pancytopenia with blasts another, and a coagulopathy a third. Run all three and the differential narrows fast. [1] [9]
References12ShowHide
- [1]Provan D; Arnold DM; Bussel JB; et al Updated international consensus report on the investigation and management of primary immune thrombocytopenia. Blood Adv, 2019.PMID 31770441
- [2]Neunert C; Terrell DR; Arnold DM; et al American Society of Hematology 2019 guidelines for immune thrombocytopenia. Blood Adv, 2019.PMID 31794604
- [3]Rodeghiero F; Stasi R; Gernsheimer T; et al Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from an international working group. Blood, 2009.PMID 19005182
- [4]Grace RF; Lambert MP; et al An update on pediatric ITP: differentiating primary ITP, IPD, and PID. Blood, 2022.PMID 34479363
- [5]Ozen S; Pistorio A; Iusan SM; et al EULAR/PRINTO/PRES criteria for Henoch-Schönlein purpura, childhood polyarteritis nodosa, childhood Wegener granulomatosis and childhood Takayasu arteritis: Ankara 2008. Part II: Final classification criteria. Ann Rheum Dis, 2010.PMID 20413568
- [6]Ozen S; Marks SD; Brogan P; et al European consensus-based recommendations for diagnosis and treatment of immunoglobulin A vasculitis-the SHARE initiative. Rheumatology (Oxford), 2019.PMID 30879080
- [7]Reamy BV; Servey JT; Williams PM Henoch-Schönlein Purpura (IgA Vasculitis): Rapid Evidence Review. Am Fam Physician, 2020.PMID 32803924
- [8]Sabra A; Benger J Meningococcal disease in children: a clinical review. Turk J Pediatr, 2011.PMID 22272447
- [9]Taylor FB Jr; Toh CH; Hoots WK; et al Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thromb Haemost, 2001.PMID 11816725
- [10]Theron A; Dautremay O; Boissier E; et al Idiopathic purpura fulminans associated with anti-protein S antibodies in children: a multicenter case series and systematic review. Blood Adv, 2022.PMID 34788405
- [11]Boyer O; Niaudet P Hemolytic-Uremic Syndrome in Children. Pediatr Clin North Am, 2022.PMID 36880929
- [12]Pierce MC; Kaczor K; Aldridge S; et al Bruising characteristics discriminating physical child abuse from accidental trauma. Pediatrics, 2010.PMID 19969620