Urticarial Vasculitis

Overview

Urticarial vasculitis is a rare form of chronic vasculitis that affects the small blood vessels in the skin, leading to urticaria (hives) that lasts longer than 24 hours and often leaves behind skin discoloration or bruising. Unlike ordinary hives, which are transient and non-inflammatory, urticarial vasculitis involves inflammation of the blood vessels (leukocytoclastic vasculitis) and may be associated with systemic symptoms. It can occur as a standalone condition or as part of an underlying systemic disorder such as lupus or hepatitis.

Causes

The exact cause of urticarial vasculitis is not always known, but it is often linked to immune system dysfunction. Possible causes and associations include:

• Autoimmune diseases (e.g., systemic lupus erythematosus, Sjögren's syndrome)

• Infections (e.g., hepatitis B or C, Epstein-Barr virus)

• Medications (e.g., antibiotics, NSAIDs, ACE inhibitors)

• Certain cancers (e.g., lymphomas, leukemias)

• Hypocomplementemia – reduced levels of complement proteins in the blood

• Idiopathic (no identifiable cause in many cases)

Symptoms

The primary symptom of urticarial vasculitis is persistent hives that differ from typical allergic urticaria. Key features include:

• Red or purple hives lasting more than 24 hours

• Burning or painful skin lesions rather than itching alone

• Residual bruising or hyperpigmentation after lesions fade

• Swelling in affected areas

In some cases, systemic symptoms may be present, especially in hypocomplementemic urticarial vasculitis:

• Fever

• Joint pain or arthritis

• Abdominal pain

• Chest discomfort or shortness of breath (if lungs are involved)

• Eye inflammation

• Kidney involvement (rare but possible)

Diagnosis

Diagnosis of urticarial vasculitis involves a combination of clinical evaluation, laboratory tests, and skin biopsy. The following steps are typically involved:

• Clinical history and examination – duration and nature of hives, systemic symptoms

• Skin biopsy – confirms leukocytoclastic vasculitis affecting small blood vessels

• Complement levels – blood tests to detect hypocomplementemia (low C3, C4)

• Autoimmune screening – ANA, anti-dsDNA, and others to rule out systemic lupus or related conditions

• Urinalysis and organ function tests – to assess systemic involvement

Treatment

Treatment depends on the severity of the symptoms and whether there is systemic involvement. Options include:

• Antihistamines – for mild skin symptoms

• Nonsteroidal anti-inflammatory drugs (NSAIDs) – to reduce pain and inflammation

• Corticosteroids – oral or topical steroids for moderate to severe inflammation

• Immunosuppressive agents – such as hydroxychloroquine, dapsone, azathioprine, or mycophenolate mofetil in more severe or systemic cases

• Biologics – such as rituximab in refractory or associated autoimmune cases

Treatment is often tailored to each individual, and long-term management may be needed in chronic cases.

Prognosis

The prognosis of urticarial vasculitis varies based on the subtype and presence of systemic involvement. Normocomplementemic cases typically have a milder course and better prognosis, often limited to skin symptoms. In contrast, hypocomplementemic urticarial vasculitis may be associated with systemic complications and require long-term immunosuppressive therapy. With appropriate management, most patients can achieve symptom control and prevent organ damage.