⚕️Emergency? Severe bleeding, stroke symptoms, fever in sickle cell disease/neutropenia, chest pain, extreme sleepiness, or little/no urine needs urgent medical care now.

Scientific condition library for pediatric blood disorders.

Use the audience switch to view parent-friendly education or healthcare professional snapshots. Each condition is organized by disease biology, diagnostic signature, acute risk, and longitudinal care principles. Content is educational and should be adapted to the child, setting, and local guidelines.

BiologyCellular and coagulation mechanisms

Red cells, platelets, neutrophils, coagulation factors, VWF, complement, and microvascular thrombi.

DiagnosticsPattern-based lab interpretation

CBC/smear, retic, ferritin, hemoglobin analysis, coagulation tests, VWF/factor assays, renal and hemolysis markers.

AcuityCritical complications clearly flagged

Fever, stroke symptoms, acute chest syndrome, critical bleeding, severe neutropenia, TTP/HUS, and organ injury.

Follow-upLongitudinal pediatric planning

Growth, school, vaccines, procedures, transfusions, genetics, iron overload, and quality of life.

Scientific orientation

Primary disease mechanisms and diagnostic signatures.

This overview is a high-level map. Individual patients require age-adjusted reference ranges, complete history, physical examination, repeat/confirmatory testing, and specialist judgment.

Disorder groupCore mechanismKey diagnostic signalsCritical complications to screen for
Iron deficiency anemiaInsufficient iron for erythropoiesisMicrocytosis, high RDW, low ferritin/transferrin saturation, reticulocyte response to ironSevere symptomatic anemia, occult blood loss, iron ingestion/toxicity
Sickle cell diseaseHbS polymerization, hemolysis, vaso-occlusionHemoglobin analysis/newborn screen, chronic hemolysis markers, genotype-specific surveillanceFever/sepsis, acute chest syndrome, stroke, splenic sequestration, aplastic crisis
ThalassemiaReduced alpha or beta globin synthesisMicrocytosis disproportionate to anemia, hemoglobin analysis, genetic testing when neededTransfusion dependence, iron overload, growth/endocrine/cardiac/hepatic complications
ITP / platelet disordersImmune platelet destruction or platelet production/function defectsPlatelet count, smear morphology, bleeding phenotype, exclusion of marrow/TMA mimicsMajor mucosal bleeding, intracranial bleeding, alternate diagnosis
NeutropeniaReduced neutrophil number from transient, immune, marrow, cyclic, or congenital causesANC trend, infection history, smear, medication/viral/immune/genetic contextFebrile severe neutropenia, invasive bacterial/fungal infection, marrow failure syndromes
Hemophilia/VWD/rare bleedingCoagulation factor, VWF, fibrinogen, or platelet function impairmentPT/aPTT/fibrinogen, VWF panel, factor assays, platelet function testingCritical-site bleeding, head trauma, surgery/procedure bleeding, joint/muscle hemorrhage
TTP/HUSThrombotic microangiopathy with MAHA and platelet consumptionSchistocytes, LDH/bilirubin/haptoglobin, creatinine/UA, ADAMTS13, Shiga toxin/complement evaluationNeurologic injury, renal failure, severe hypertension, cardiac/pulmonary involvement

Iron Deficiency Anemia

A common pediatric anemia caused by insufficient iron for hemoglobin production.

AnemiaMicrocyticCommon
Lab decoder
Core biologyIron-restricted erythropoiesisInsufficient iron limits hemoglobin synthesis and red-cell production.
Diagnostic signatureMicrocytic anemia with depleted iron storesFerritin and transferrin saturation are interpreted with inflammation and history.
Management principleReplete iron and identify causeDietary counseling, adherence support, and evaluation for blood loss or malabsorption when indicated.
Acuity screenSymptomatic severe anemia or ingestionCardiorespiratory symptoms and iron overdose require urgent action.

What parents should know

Iron helps red blood cells carry oxygen. Children can become iron deficient from low dietary iron, too much cow’s milk, rapid growth, menstruation, or blood loss.

  • Symptoms may include tiredness, pale skin, fast heartbeat, headaches, poor appetite, or pica such as craving ice or dirt.
  • Treatment often includes iron-rich foods and an iron medicine plan from your clinician.
  • Improvement is monitored with repeat blood tests; iron stores usually take longer to rebuild than hemoglobin.

Call urgently if

  • Your child has chest pain, fainting, severe shortness of breath, or extreme sleepiness.
  • There is black stool, blood in stool or urine, heavy menstrual bleeding with dizziness, or rapid worsening pallor.
  • A young child may have swallowed iron tablets; iron overdose is an emergency.

Clinical snapshot

Typical pattern: low hemoglobin, low MCV/MCH, high RDW, low ferritin or low transferrin saturation. Reticulocyte response after therapy supports diagnosis.

  • Assess diet, cow’s milk intake, growth, menses, GI symptoms, pica, lead exposure, prematurity, and family history.
  • Consider CRP with ferritin when inflammation may confound interpretation.
  • Screen for celiac disease, inflammatory bowel disease, or occult blood loss when history or response is atypical.

Referral / escalation

  • Severe symptomatic anemia, diagnostic uncertainty, pancytopenia, hemolysis, poor response despite adherence, or need for IV iron/transfusion.
  • Microcytosis disproportionate to anemia, normal ferritin, high RBC count, or relevant ancestry should prompt consideration of thalassemia trait.

Sickle Cell Disease

An inherited hemoglobin disorder where red cells can sickle, block blood flow, and break down early.

HemoglobinopathyFever emergencyPain crisis
Urgent signs
Core biologyHbS polymerization and vaso-occlusionSickling drives hemolysis, endothelial activation, ischemia, and pain.
Diagnostic signatureHemoglobin genotype plus hemolysis profileNewborn screening or hemoglobin analysis guides phenotype-specific surveillance.
Management principlePrevention plus rapid complication careVaccines, fever plans, hydroxyurea/transfusion strategies, and organ screening.
Acuity screenFever, acute chest, stroke, sequestrationTime-sensitive complications should bypass routine pathways.

What parents should know

Sickle cell disease is lifelong, but excellent preventive care can greatly reduce complications. Children need a hematology team, vaccines, fever plans, pain plans, and regular screening.

  • Pain episodes can happen in arms, legs, back, belly, or chest.
  • Fever can be serious because some children are at higher risk for severe bacterial infection.
  • Hydroxyurea and transfusion programs are preventive options for many children.

Seek emergency care for

  • Fever, chest pain, trouble breathing, severe headache, weakness on one side, seizures, or confusion.
  • Severe belly pain, sudden enlarging spleen, marked paleness, extreme tiredness, or dizziness.
  • Pain not controlled by the home plan, dehydration, persistent vomiting, or priapism.

Clinical snapshot

Confirm genotype from newborn screen/electrophoresis/HPLC. Maintain preventive care: immunizations, penicillin where indicated, transcranial Doppler screening for eligible genotypes, hydroxyurea counseling, and complication surveillance.

  • Fever requires prompt assessment for sepsis; obtain cultures and give empiric antibiotics per local protocol.
  • Evaluate respiratory symptoms for acute chest syndrome; hypoxia, infiltrate, or fever requires escalation.
  • Neurologic symptoms are stroke until proven otherwise and need emergent hematology/neurology coordination.

Complication prompts

  • Acute anemia: reticulocyte count, bilirubin/LDH, spleen exam, parvovirus consideration.
  • Recurrent severe pain, acute chest, abnormal TCD, stroke, or organ complications may require disease-modifying therapy or transfusion programs.
  • Avoid delays in analgesia and hydration assessment; use individualized pain plans where available.

Thalassemia

Inherited conditions where the body makes less alpha or beta globin, affecting hemoglobin production.

HemoglobinopathyMicrocyticGenetic counseling
Family FAQ
Core biologyImbalanced globin-chain synthesisIneffective erythropoiesis and hemolysis vary by genotype.
Diagnostic signatureMicrocytosis with hemoglobin/genetic testingDistinguish trait from iron deficiency and transfusion-dependent disease.
Management principlePhenotype-directed lifelong surveillanceTransfusions, chelation, endocrine/cardiac/hepatic monitoring, and genetic counseling.
Acuity screenSevere anemia or transfusion reactionRapid pallor, cardiopulmonary symptoms, or reaction symptoms need urgent care.

What parents should know

Thalassemia can range from a harmless carrier state to severe anemia needing regular transfusions. It is inherited, so family testing and counseling may be important.

  • Thalassemia trait often causes small red blood cells but may not need treatment.
  • Children with transfusion-dependent thalassemia need specialized care to manage anemia and iron overload.
  • Iron should not be given unless iron deficiency is proven.

Call urgently if

  • Your child has severe pallor, fainting, chest pain, trouble breathing, or fast heartbeat at rest.
  • There are transfusion reactions such as fever, hives, breathing trouble, dark urine, or back pain after transfusion.
  • There are signs of infection, severe abdominal swelling, or extreme fatigue.

Clinical snapshot

Microcytosis with normal iron stores, relatively high RBC count, target cells, family history, or relevant ancestry should raise suspicion. Beta-thalassemia trait often shows elevated HbA2; alpha-thalassemia may require genetic testing.

  • Differentiate iron deficiency from thalassemia trait; both may coexist.
  • For transfusion-dependent disease: monitor alloimmunization, iron overload, endocrine, cardiac, hepatic, bone, and growth complications.
  • Coordinate genetic counseling and family testing.

Referral / escalation

  • Suspected major/intermedia phenotype, symptomatic anemia, transfusion need, splenomegaly, growth delay, or complex genetic counseling.
  • Avoid empiric long-term iron in microcytosis without evidence of iron deficiency.

Immune Thrombocytopenia (ITP)

An immune condition where platelets are low, causing easy bruising or petechiae.

PlateletsBruisingOften self-limited
Activity tips
Core biologyImmune-mediated platelet clearancePlatelets are destroyed and/or production is impaired through immune mechanisms.
Diagnostic signatureIsolated thrombocytopeniaTypical ITP requires a reassuring CBC differential and smear.
Management principleTreat bleeding phenotype, not number aloneObservation is often appropriate; therapy depends on bleeding severity and context.
Acuity screenHead injury or major mucosal bleedingNeurologic symptoms or persistent bleeding require emergency protocols.

What parents should know

Platelets help stop bleeding. In ITP, the immune system removes platelets too quickly. Many children recover over time, and treatment depends more on bleeding than the number alone.

  • Signs include tiny red-purple dots, bruises, nosebleeds, gum bleeding, or heavy periods.
  • Your team may advise avoiding aspirin/ibuprofen and high-impact activities while platelets are very low.
  • Some children are watched closely; others receive medicines to raise platelets faster.

Emergency signs

  • Head injury, severe headache, repeated vomiting, confusion, weakness, or seizure.
  • Bleeding that will not stop, blood in stool/urine, coughing/vomiting blood, or very heavy menstrual bleeding.
  • New fever, bone pain, weight loss, swollen glands, or unusual fatigue should be discussed promptly.

Clinical snapshot

ITP is typically isolated thrombocytopenia with otherwise reassuring CBC and smear. Evaluate for alternate diagnoses when anemia, neutropenia, blasts, organomegaly, lymphadenopathy, systemic symptoms, or atypical history is present.

  • Bleeding severity guides management; platelet count is not the only driver.
  • Options include observation, corticosteroids, IVIG, anti-D in appropriate patients/settings, and second-line therapies for persistent/chronic disease.
  • Review medication exposures, recent infection/vaccination, autoimmune features, and family history.

Referral / escalation

  • Mucosal bleeding, severe thrombocytopenia with risk factors, atypical labs, chronic/refractory disease, suspected inherited thrombocytopenia, or urgent procedure.
  • Intracranial hemorrhage concern requires emergent hematology, neuroimaging, and institution-specific critical bleeding protocol.

Neutropenia

A low number of neutrophils, the white blood cells that help fight bacterial and fungal infections.

ANCFever riskInfection
Fever guide
Core biologyReduced circulating neutrophilsEtiologies include post-viral, autoimmune, medication, cyclic, congenital, marrow, and immune causes.
Diagnostic signatureANC trend plus infection phenotypeSeverity, duration, age, ancestry, and clinical context determine risk.
Management principleRisk-stratified fever planningSevere chronic neutropenia requires specialist evaluation and individualized infection precautions.
Acuity screenFever in severe neutropeniaPrompt empiric evaluation is time-sensitive in high-risk patients.

What parents should know

Neutropenia means fewer infection-fighting neutrophils. Some children have temporary neutropenia after viral illness; others have chronic or inherited forms needing specialist care.

  • The absolute neutrophil count, or ANC, helps estimate infection risk.
  • Good hand hygiene, prompt fever plans, and regular follow-up are important.
  • Children with severe or chronic neutropenia may need extra evaluation.

Call urgently for

  • Fever, chills, appearing very unwell, fast breathing, severe mouth sores, skin infection, or pain around the bottom.
  • Any fever plan given by your hematologist, oncologist, or immunologist should be followed exactly.
  • Do not delay care for fever in severe neutropenia.

Clinical snapshot

Interpret ANC by age, ancestry, clinical context, severity, duration, and infection history. Transient post-viral neutropenia is common; severe, recurrent, or syndromic cases require workup.

  • Trend CBC/differential; examine smear. Assess medications, viral illnesses, autoimmune disease, nutritional deficiencies, immunodeficiency, marrow failure, and congenital syndromes.
  • Recurrent fevers at regular intervals suggest cyclic neutropenia; serial CBCs may help.
  • Fever with severe neutropenia requires prompt empiric management per local febrile neutropenia pathways.

Referral / escalation

  • ANC persistently severe, serious/recurrent bacterial infections, oral ulcers/gingivitis, failure to thrive, dysmorphism, other cytopenias, splenomegaly, or concerning smear.
  • Consider marrow/genetic/immunology evaluation when congenital, marrow failure, or immune dysregulation features are present.

Hemophilia A & B

Inherited bleeding disorders caused by low factor VIII or factor IX activity.

BleedingFactor VIII/IXHead injury urgent
School plan
Core biologyFactor VIII or IX deficiencyReduced thrombin generation predisposes to joint, muscle, and procedure bleeding.
Diagnostic signatureFactor activity assayaPTT may be prolonged, but mild disease may require targeted testing.
Management principleComprehensive hemophilia careFactor/non-factor prophylaxis, inhibitor surveillance, joint health, and home education.
Acuity screenHead trauma or critical-site bleedingHemostatic therapy should not be delayed when serious bleeding is suspected.

What parents should know

Hemophilia can cause bleeding into joints, muscles, or after injury/procedures. Modern care includes factor replacement and preventive therapies that help children live active lives.

  • Joint bleeds may feel warm, swollen, painful, or cause limping or reduced movement.
  • Families often learn a home treatment plan and when to go directly to the emergency department.
  • Medical alert identification and sharing the emergency plan with school or sports staff is important.

Treat as urgent

  • Head injury, severe headache, neck pain, vomiting, confusion, seizure, or weakness.
  • Throat/neck swelling, trouble breathing, belly trauma, major muscle swelling, or suspected joint bleed.
  • Bleeding after surgery, dental work, circumcision, or injury that does not stop.

Clinical snapshot

Hemophilia A: factor VIII deficiency. Hemophilia B: factor IX deficiency. Screening may show prolonged aPTT with normal PT/platelets, but mild disease can be subtle. Confirm with factor assays.

  • Bleeding phenotype correlates with factor activity but individual variability exists.
  • Management may include factor concentrates, non-factor prophylaxis for hemophilia A, desmopressin for selected mild hemophilia A, antifibrinolytics for mucosal bleeding, and inhibitor surveillance.
  • For suspected serious bleed, contact hematology urgently and do not wait for imaging before hemostatic therapy if known severe hemophilia and protocol supports.

Referral / escalation

  • Any confirmed/suspected hemophilia should be linked to a hemophilia treatment center.
  • Urgent procedure, trauma, suspected inhibitor, high-titer inhibitor history, or critical-site bleeding requires specialized management.

Von Willebrand Disease (VWD)

A common inherited bleeding disorder affecting platelet adhesion and factor VIII protection.

BleedingNosebleedsHeavy menses
Bleeding kit
Core biologyVWF quantity or function abnormalityImpaired platelet adhesion and factor VIII stabilization produce mucocutaneous bleeding.
Diagnostic signatureVWF antigen/activity and factor VIIILevels vary with stress, inflammation, hormones, blood type, and age; repeat testing may be needed.
Management principleType-specific bleeding planAntifibrinolytics, desmopressin trials where appropriate, VWF concentrates, and procedural planning.
Acuity screenHeavy mucosal bleeding or traumaPersistent bleeding, severe menses, or head injury require escalation.

What parents should know

VWD can cause nosebleeds, easy bruising, heavy periods, or prolonged bleeding after dental work or surgery. Many children do very well with a clear bleeding plan.

  • Treatments may include nose care, antifibrinolytic medicine, desmopressin for selected types, or VWF-containing concentrates.
  • Testing can vary over time and may need repeating.
  • Tell doctors and dentists about VWD before procedures.

Call urgently for

  • Bleeding that does not stop with the home plan, vomiting/coughing blood, black stool, or blood in urine.
  • Head injury, severe headache, confusion, or vomiting after trauma.
  • Heavy menstrual bleeding with dizziness, fainting, chest pain, or soaking products very rapidly.

Clinical snapshot

Evaluate with bleeding history tool where appropriate, CBC/ferritin, PT/aPTT, VWF antigen, VWF activity assay, and factor VIII; repeat testing may be needed because VWF is stress/inflammation/hormone responsive.

  • Classify type to guide therapy; desmopressin trial may be appropriate in selected patients but is contraindicated/ineffective in others.
  • Assess heavy menstrual bleeding and iron deficiency proactively.
  • Coordinate peri-procedural plans with hematology, dentistry, surgery, and anesthesia.

Referral / escalation

  • Abnormal VWF testing, significant mucosal bleeding, heavy menses, procedure planning, suspected type 2/3 disease, or poor response to initial measures.
  • Normal initial labs do not exclude mild bleeding disorder when history is compelling.

Rare Bleeding Disorders

Uncommon inherited or acquired disorders of clotting factors, fibrinogen, or platelet function.

BleedingRareSpecialist care
Workup
Core biologyRare factor, fibrinogen, or platelet defectsPhenotypes vary from umbilical bleeding to delayed postoperative bleeding.
Diagnostic signatureTargeted coagulation and platelet testingPT/aPTT may be normal in factor XIII and platelet function disorders.
Management principleSpecialist-defined hemostatic planDiagnosis-specific replacement, antifibrinolytics, procedure planning, and family counseling.
Acuity screenCritical-site or delayed bleedingHead/neck/abdominal/joint/muscle bleeding requires urgent specialist input.

What parents should know

Some children bleed because of rare clotting factor or platelet function problems. The exact diagnosis matters because treatments differ.

  • Bleeding can include nosebleeds, bruising, mouth bleeding, heavy periods, umbilical stump bleeding, joint/muscle bleeding, or bleeding after procedures.
  • A hematology team may order specialized tests not available in every lab.
  • Families should keep an emergency plan and share it with schools and hospitals.

Urgent signs

  • Bleeding in the head, neck, chest, abdomen, joint, muscle, or after significant trauma.
  • Persistent bleeding despite pressure or prescribed treatment.
  • Newborn bleeding, umbilical stump bleeding, or delayed bleeding after surgery needs prompt review.

Clinical snapshot

Consider factor I, II, V, VII, X, XI, XIII deficiencies, combined factor deficiencies, platelet function disorders, and connective tissue mimics. PT/aPTT patterns can guide testing, but factor XIII deficiency and platelet function disorders may have normal PT/aPTT.

  • Phenotype, family history/consanguinity, timing of bleeding, and procedure bleeding history are essential.
  • Initial studies: CBC/smear, PT/INR, aPTT, fibrinogen, VWD panel; then targeted factor assays and platelet function testing.
  • Coordinate specimen handling with a coagulation lab to avoid false results.

Referral / escalation

  • Any suspected rare bleeding disorder should be referred to pediatric hematology/hemophilia center.
  • Critical-site bleeding, surgery, delivery/newborn planning, or recurrent significant mucosal bleeding requires specialist protocol.

Thrombotic Thrombocytopenic Purpura (TTP)

A rare, life-threatening thrombotic microangiopathy involving low platelets and hemolytic anemia.

EmergencyMAHAADAMTS13
MAHA pathway
Core biologyADAMTS13 deficiency-mediated TMAUltra-large VWF multimers promote platelet-rich microthrombi and organ ischemia.
Diagnostic signatureMAHA plus thrombocytopeniaSchistocytes, hemolysis markers, organ injury, and ADAMTS13 testing guide diagnosis.
Management principleImmediate specialist-directed therapyDo not wait for the historical pentad; early plasma exchange-based care may be lifesaving.
Acuity screenNeurologic/cardiac/renal involvementTTP is an emergency until excluded in the right phenotype.

What parents should know

TTP is rare in children but serious. Tiny clots can form in small blood vessels, using up platelets and damaging red blood cells. It requires emergency hospital care.

  • Symptoms may include bruising, tiny red spots, pale or yellow skin, severe headache, confusion, weakness, seizures, fever, or dark urine.
  • TTP is not something to watch at home.
  • Early treatment is very important.

Go to emergency care now for

  • Confusion, seizure, severe headache, weakness, trouble speaking, or fainting.
  • New bruising/petechiae with extreme fatigue, pallor, jaundice, or dark urine.
  • Reduced urination, chest pain, shortness of breath, or a very unwell child.

Clinical snapshot

Suspect TTP with thrombocytopenia plus microangiopathic hemolytic anemia: schistocytes, elevated LDH, indirect bilirubin, low haptoglobin, negative/appropriate DAT context, and organ involvement. Pediatric cases may be immune-mediated or congenital ADAMTS13 deficiency.

  • Send ADAMTS13 activity/inhibitor before plasma therapy if this does not delay treatment.
  • Consult hematology/transfusion medicine urgently; treatment often includes plasma exchange for immune TTP plus immunosuppression and adjuncts depending on age, setting, and protocol.
  • Platelet transfusion is generally avoided unless life-threatening bleeding/procedure and specialist guidance.

Immediate priorities

  • Differentiate from HUS, DIC, severe hypertension, autoimmune disease, infection, malignancy, drug-induced TMA, and complement-mediated TMA.
  • Do not wait for pentad; classic fever/neuro/renal findings may be incomplete.
  • Early specialist-directed therapy is time critical.

Hemolytic Uremic Syndrome (HUS)

A thrombotic microangiopathy causing hemolytic anemia, low platelets, and kidney injury.

EmergencyKidneyMAHA
MAHA pathway
Core biologyTMA with kidney-predominant injurySTEC-HUS and complement-mediated HUS require different diagnostic and management pathways.
Diagnostic signatureMAHA, thrombocytopenia, AKICreatinine/UA, stool Shiga toxin testing, hemolysis markers, and complement evaluation when indicated.
Management principleNephrology-centered supportive careFluid balance, hypertension, electrolytes, dialysis criteria, and complement blockade consideration.
Acuity screenOliguria, hypertension, neurologic symptomsRenal or neurologic deterioration requires urgent hospital care.

What parents should know

HUS can happen after certain diarrheal infections, especially bloody diarrhea, or from rare complement-related causes. It can injure the kidneys and needs hospital care.

  • Symptoms may include less urine, swelling, pallor, fatigue, bruising, vomiting, belly pain, or high blood pressure.
  • Do not give anti-diarrheal medicines unless your clinician says to.
  • Some children need fluids, blood pressure care, transfusions, dialysis, or complement-targeted treatment depending on the type.

Seek emergency care for

  • Bloody diarrhea with reduced urination, pallor, bruising, swelling, or unusual sleepiness.
  • No urine or very little urine, severe headache, seizure, confusion, chest pain, or trouble breathing.
  • Known HUS with worsening blood pressure, swelling, or fatigue.

Clinical snapshot

Triad: MAHA, thrombocytopenia, acute kidney injury. Evaluate for Shiga toxin-associated HUS and complement-mediated HUS, while considering TTP and other TMAs.

  • Labs: CBC/smear, CMP/creatinine, LDH, bilirubin, haptoglobin, retic, UA, urine protein, stool Shiga toxin/PCR/culture, coagulation studies, complement evaluation when indicated.
  • Supportive nephrology care is central; avoid unnecessary platelet transfusion unless bleeding/procedure. Manage hypertension, fluid balance, electrolytes, and dialysis indications.
  • Complement-mediated HUS requires urgent specialist consideration of complement blockade and genetic/autoantibody evaluation.

Referral / escalation

  • Any suspected HUS warrants hospital assessment and nephrology/hematology coordination.
  • Neurologic symptoms, severe hypertension, oliguria/anuria, significant electrolyte derangement, or uncertain TMA type requires urgent escalation.

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