What is the appropriate workup and management for a patient presenting with purpura?

Workup and Management of Purpura

The approach to purpura depends critically on its morphology and clinical context: palpable purpura requires evaluation for cutaneous vasculitis with skin biopsy and targeted laboratory testing, while retiform purpura demands urgent assessment for vascular occlusion or thrombosis, and non-palpable purpura with thrombocytopenia necessitates immediate platelet count assessment and consideration of immune thrombocytopenic purpura (ITP) or thrombotic microangiopathies.

Initial Assessment and Risk Stratification

Determine Purpura Type and Severity

• Palpable purpura indicates cutaneous vasculitis, most commonly from drug reactions, infections, or collagen vascular disease 1
• Retiform purpura (branching, net-like pattern) signals vascular compromise with cutaneous ischemia and requires urgent evaluation for conditions with high morbidity and mortality 2, 3
• Non-palpable purpura with thrombocytopenia suggests platelet disorders including ITP or thrombotic microangiopathies 4, 5

Assess Bleeding Severity

• Severe bleeding (organ- or life-threatening) requires immediate treatment regardless of etiology 4
• Moderate bleeding or increased bleeding risk warrants consideration for treatment 4
• Mild purpura alone without significant thrombocytopenia or bleeding may be managed expectantly 4

Diagnostic Workup

For Palpable Purpura

• Complete blood count with differential to assess for thrombocytopenia, anemia, or leukocytosis 1
• Skin biopsy is essential when the cause is unclear from history and physical examination 1
• Targeted laboratory testing based on clinical suspicion: antinuclear antibodies, complement levels, cryoglobulins, hepatitis serologies, blood cultures if febrile 1
• Review medication history for drug-induced vasculitis 1

For Retiform Purpura (Urgent Workup)

• Immediate assessment for sepsis (meningococcemia, streptococcal infection), disseminated intravascular coagulation, purpura fulminans, and catastrophic antiphospholipid syndrome 3, 6
• Blood cultures, coagulation studies (PT, PTT, fibrinogen, D-dimer), antiphospholipid antibodies 3
• Consider rickettsial illness in appropriate clinical context, even without classic findings like eschar 7
• Skin biopsy to evaluate for vessel wall damage versus luminal occlusion 2

For Non-Palpable Purpura with Thrombocytopenia

• Platelet count is the critical first test 4
• Peripheral blood smear to assess for schistocytes (suggesting thrombotic microangiopathy) 5
• ADAMTS13 activity testing if thrombotic thrombocytopenic purpura (TTP) is suspected based on clinical presentation or PLASMIC score 8, 5
• For suspected ITP: exclude secondary causes through HIV, hepatitis C testing, and other directed studies based on clinical presentation 4

Management Approach

For ITP in Children

Treatment is necessary for all children with severe bleeding and should be considered for moderate bleeding or increased bleeding risk 4

First-Line Treatment Options:

• IVIg 0.8-1 g/kg as single dose: Effective in >80% of children, raises platelets within 1-2 days, with transient side effects (headache, fever) 4
• Prednisone 1-2 mg/kg/day for maximum 14 days OR 4 mg/kg/day for 3-4 days: Effective in 72-88% within 72 hours, but use for shortest duration possible due to side effects 4
• IV anti-D immunoglobulin for Rh(D)-positive children: Effective but carries risk of hemolysis, particularly in patients with comorbidities 4
• Watch and wait: Approximately two-thirds of children improve spontaneously over days to 6 months; appropriate for stable patients with platelet counts 20-30 × 10⁹/L without significant bleeding 4

Emergency Treatment:

• For life-threatening bleeding: Administer 2-3 fold larger platelet transfusion dose PLUS high-dose IV corticosteroids PLUS IVIg or IV anti-D simultaneously 4

For Palpable Purpura

• Many cases are idiopathic and self-limited, requiring only observation 1
• When treatment is necessary: Dapsone, colchicine, or systemic corticosteroids are useful options 1
• Treat underlying cause when identified (discontinue offending drug, treat infection, manage collagen vascular disease) 1

For Retiform Purpura/Purpura Fulminans

• Immediate antibiotic administration for suspected sepsis (N. meningitidis, Streptococcus) 6
• Volume resuscitation, ventilatory and inotropic support as needed 6
• Early fasciotomies may limit the level of amputation when performed during initial management 6
• Consider protein C replacement in appropriate cases 6
• Doxycycline for rickettsial illness when suspected 7

For TTP/Thrombotic Microangiopathies

• Therapeutic plasma exchange (TPE) should be initiated within one day of admission 8, 5
• Corticosteroids are administered in the vast majority of cases 8
• Rituximab should be used as it is protective against relapses and is cost-effective 8
• TTP cases should be managed within designated regional centers per specialized service guidelines 5

Critical Pitfalls to Avoid

• Do not delay treatment in retiform purpura or purpura fulminans—these conditions have high mortality and require immediate intervention 3, 6
• Do not use prolonged corticosteroids in children with ITP due to serious side effects; use only to maintain hemostatic platelet count for shortest time possible 4
• Do not miss TTP—delayed diagnosis and treatment significantly increases mortality; ensure ADAMTS13 testing and rapid TPE initiation 8, 5
• Do not give IV anti-D to patients with comorbidities without careful consideration of hemolysis risk 4
• Do not forget that approximately two-thirds of children with ITP improve spontaneously—avoid overtreatment in stable patients 4

Special Considerations

• Children with persistent ITP and platelet counts 10-30 × 10⁹/L without serious bleeding but troublesome purpura may benefit from treatment, particularly adolescents concerned about appearance 4
• Families should carry emergency information cards and consider medical alert bracelets for children with chronic ITP 4
• Menstruation in adolescent girls with ITP can be managed with antifibrinolytic agents and hormonal medication 4