Differentials
Idiopathic thrombocytopenic purpura (ITP)
SIGNS / SYMPTOMS
Rash of ITP may also have petechiae. Arthralgias and abdominal pain are uncommon.
INVESTIGATIONS
Platelet level is low in ITP, but normal in IgAV.
Hypersensitivity vasculitis
SIGNS / SYMPTOMS
Usually no renal involvement.
INVESTIGATIONS
Skin biopsy may show leukocytoclastic vasculitis, but no IgA deposition.
Rheumatic fever
SIGNS / SYMPTOMS
May have similar clinical features to IgAV; however, the rash in rheumatic fever is erythema marginatum, and not palpable purpura.
INVESTIGATIONS
Predominance of deposition of IgA on biopsy characterises IgAV. Increased anti-streptolysin-O antibody titres have been reported in both rheumatic fever and IgAV, therefore making them difficult to distinguish.
Meningococcal septicaemia
SIGNS / SYMPTOMS
May have similar clinical features; rash may also have petechiae.
The child is usually very unwell with meningococcal septicemia.
INVESTIGATIONS
Abnormal coagulation studies and low platelet counts are seen in septicaemia. Positive septic (infection) screen is seen in meningococcal septicaemia. These studies are normal in IgAV.
Haemolytic uraemic syndrome (HUS)
SIGNS / SYMPTOMS
May have similar clinical features; rash may also have petechiae. Diarrhoea is common in HUS.
INVESTIGATIONS
Haemolytic anaemia, with elevated reticulocyte counts and low haptoglobin levels, and low platelets are seen in HUS. Stool studies may be helpful in HUS; these studies are normal in IgAV and abnormal in HUS.
IgA nephropathy
SIGNS / SYMPTOMS
Rash, abdominal pain, and arthritis are generally not present. Patients are usually aged between 20 to 40 years.
INVESTIGATIONS
Renal biopsy shows similar findings with IgA nephropathy and IgAV. However, patients with IgA nephropathy do not have the other clinical manifestations of IgAV.
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