26th February 2025

Immune complex-associated vasculitides

Anti-glomerular basement membrane (GBM) disease

This is also called Goodpasture disease.

This is another pulmonary-renal syndrome. It affects pulmonary and glomerular capillaries and is caused by deposition of anti-basement membrane antibodies.

Most patients present with rapidly progressive glomerulonephritis, occasionally with concomitant pulmonary haemorrhage. Other manifestations of respiratory involvement include dyspnoea and cough.

Blood tests show an AKI, and anti-GBM antibodies may be present. Urinalysis shows proteinuria and haematuria, with red cell and granular casts on microscopy. Chest imaging may show pulmonary infiltrates. Lung function testing may show an increased DLCO if pulmonary haemorrhage is present. Renal biopsy is required for formal diagnosis unless contraindicated. This will reveal linear deposition of IgG along glomerular capillaries.

IgA vasculitis (Henoch Schönlein purpura, HSP) 

This is classically described in children; however can occur in people at any age.

Palpable purpura is the most common presenting symptom, usually over the buttocks and legs, alongside arthritis, abdominal pain and renal involvement. Arthritis is usually oligoarticular and involves large joints of the lower limbs. GI involvement can range from mild abdominal pain with nausea and vomiting to intussusception, although this is rare in adults. Renal involvement is more common in adults and carries a higher risk of ESRF than in children.

There are no specific blood tests for HSP, although serum IgA can be raised. Biopsy is generally not required in children; however, is often necessary in adult patients. 

HSP is generally self-limiting, and management is supportive. The use of glucocorticoids is controversial.

Hypocomplimentaemic urticarial vasculitis

This is a rare condition which causes a combination of urticaria and cutaneous vasculitis, with purpura and livedo reticularis. Extra-cutaneous manifestations can occur similarly to other forms of vasculitis, with arthralgia or arthritis, pulmonary involvement, and proteinuria or haematuria. 

Blood tests will often show raised ESR, reduced complement, positive ANA and positive C1q antibodies.

Cryoglobulinaemic vasculitis

This is a rare form of vasculitis caused by the presence of cryoglobulin immune complexes in blood vessels. Most commonly, this involves the skin, kidneys and peripheral nerves. There are three types of cryoglobulins:

Table 5 Classification of cryoglobulinaemia