Paediatric Purpuric Rash

Differential

• Pathophysiology
  • Vascular dysfunction
  • Platelet dysfunction/deficiency
  • Coagulation disorder
• Always consider:
  • Meningococcaemia
  • Septicaemia
  • HSP
  • ITP
  • Leukaemia
  • Viral illness
  • NAI

Fever and petechiae (Cameron)

• Pinpoint, non-blanching spots <2mm
• Majority have no cause identified – presumed viral origin
• <5% will have meningococcaemia
• DDx
  • Viral (enterovirus/influenza)
  • Meningococcaemia
  • Sepsis (S. pneumoniae/H. influenzae)
  • HSP, ITP, leukaemia
  • Mechanical causes

• In the unwell child
  • As evidenced by:
    • Impaired consciousness
    • Abnormal vital signs
    • Poor perfusion
    • Any purpuric lesions >2mm
    • WCC >15 or <5
    • CRP >8
  • Presume meningococcaemia until proven otherwise

• In the well child
  • Consider mechanical causes
    • Discharge with planned review within 24 hours
  • If no mechanical cause identified, likely viral
    • FBC, CRP and BC
    • Observe for 4 hours
    • If results normal and looks well, discharge with review next day
    • If received antibiotics, consider partially treated meningitis or sepsis (lower threshold for admission or early review)

Thrombocytopaenic purpura

• Idiopathic thrombocytopaenic purpura (ITP) is the most common cause often with intercurrent viral infection
• Acquired thrombocytopaenia due to shortened platelet circulating survival time (usually no autoantibodies detected in children) in the absence of other coagulation disorders
• Acute (90%)
  • Self-limiting with spontaneous resolution within 6 months (usually within 2 months)
• Chronic (10%)
  • Does not remit within 6 months and usually seen in adults
• Usually bleeding and petechiae alone – if raised petechiae/purpura should consider vasculitis, IE, SLE or RA
• Hepatosplenomegaly suggests alternative diagnosis
• Oral bleeding, epistaxis, haematuria and GI bleeding is relatively rare

• Incidence of ICH is  far <1%
• Need to exclude aplastic anaemia and leukaemia
  • Lymphadenopathy/splenomegaly/pallor/bloods
• FBC normal apart from low platelet count (hallmark of disease) – platelets are large, well granulated and highly functional
• Consider drug-induced thrombocytopaenia (chloramphenicol/antithyroid medications)

• Management
  • Oral steroids improve platelet count more quickly than no treatment but no evidence on benefit w.r.t. morbidity, chronic ITP or mortality
  • Conservative outpatient management
    • Most patients with Plt >20 require no specific treatment. Need activity modification and avoidance of antiplatelet agents
    • Criteria: unequivocal diagnosis, no active bleeding, otherwise well, socially okay, reassured parents, follow-up with Paediatricians within days
  • Conservative inpatient management
    • Uncertain Dx
  • Inpatient treatment
    • Active bleeding usually treated with oral prednisolone 2-4mg/kg/day for 2 weeks then tapered
      Warranted if mucous membrane bleeding or more extensive cutaneous involvement
    • Serious bleeding episodes or surgery warrant IVIG
    • Platelet transfusion only indicated for ICH (as immediately destroyed)
  • Splenectomy only in rare chronic ITP

Leukaemia

• Suspect if pallor, splenomegaly, tiredness, limb pain, malaise and gum hypertrophy
• Thrombocytopaenia is usually present

Coagulation disorders

• Consider if FHx, hx of joint pain/swelling or bleeding from other sites

Papular-purpuric gloves and sock syndrome

• Due to Parvovirus B19 
• Seen in adolescents with vague fever, fatigue, pains and petechial/purpuric lesions in glove/stocking distribution
• Eruption clears within 2 weeks
• Infective while rash is present (unlike erythema infectiosum in children)

Last Updated on November 22, 2021 by Andrew Crofton