Urticarial vasculitis

Urticarial Vasculitis

Diagram of the complement pathway, which is involved in urticarial vasculitis.

Urticarial vasculitis is a rare form of vasculitis characterized by the presence of urticarial lesions that are associated with histological evidence of leukocytoclastic vasculitis. Unlike typical urticaria, the lesions in urticarial vasculitis are often painful, last longer than 24 hours, and may leave residual hyperpigmentation.

Pathophysiology

Urticarial vasculitis is associated with the activation of the complement system, particularly the classical pathway. The complement pathway is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells. In urticarial vasculitis, the activation of the complement system leads to inflammation and damage to the small blood vessels in the skin.

Clinical Features

Patients with urticarial vasculitis typically present with:

• Urticarial lesions that are painful or burning rather than itchy.
• Lesions that persist for more than 24 hours.
• Possible systemic symptoms such as fever, arthralgia, and abdominal pain.
• Residual hyperpigmentation or purpura after the lesions resolve.

Diagnosis

The diagnosis of urticarial vasculitis is confirmed by a skin biopsy showing leukocytoclastic vasculitis. Laboratory tests may reveal low levels of complement components, such as C3 and C4, indicating complement consumption.

Treatment

Treatment of urticarial vasculitis depends on the severity of the disease and the presence of systemic involvement. Options include:

• Antihistamines for symptomatic relief.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation.
• Corticosteroids for more severe cases.
• Immunosuppressive agents such as azathioprine or cyclophosphamide for refractory cases.

Prognosis

The prognosis of urticarial vasculitis varies. Some patients experience a self-limited course, while others may have chronic or recurrent disease. The presence of systemic involvement can affect the overall prognosis.

Related Pages

• Vasculitis
• Urticaria
• Complement system
• Immune system