What is urticarial vasculitis?
Urticarial vasculitis is a skin condition characterized by an inflammation of blood vessels. Patches on the skin seem to resemble urticaria — hives or swelling on the skin surface. However, when the skin is examined under a microscope, inflamed blood vessels can be seen.
Urticarial vasculitis is a rare autoimmune disorder. It can affect people at any age but is more common in adults between ages 30 and 40 years. Twice as many women are affected as men. Although its first symptom is similar to urticaria, only about 2% of people with chronic urticaria have urticarial vasculitis.
Signs and symptoms of urticarial vasculitis
The first symptom is typically an eruption of raised red patches (wheals) on the skin, which may often be painful or feel like it’s burning. For some people, the wheals feel itchy. These red patches may have a white center or small, round red spots (petechiae) may appear.
These skin lesions usually last for more than 24 hours and as they heal will leave a skin discoloration that looks like a bruise.
Pain in one or more of the joints occurs in about half of those with a specific type of urticarial vasculitis called hypocomplementemic urticarial vasculitis (HUV).
Swollen lymph nodes
Shortness of breath
This can happen when the immune system attacks the lungs, which leads to inflammation and scarring. This affects how a person breathes.
Types of urticarial vasculitis
There are two subtypes of urticarial vasculitis. The difference is in the number of complement proteins. The complement system refers to more than 30 proteins that are found in our blood. Their main function is to defend the body against infections, such as by destroying bacteria and promoting the effectiveness of antibodies.
Normocomplementemic urticarial vasculitis (NUV)
People with NUV have skin lesions and normal levels of the complement protein C1q.
Hypocomplementemic urticarial vasculitis (HUV)
This is the more severe form, with symptoms that affect other parts of the body or even the whole body (systemic), such as joint pain or kidney and lung problems. Those with HUV have lower than normal levels of C1q proteins and higher levels of C1q antibodies. HUV has been found almost exclusively in women.
Some researchers also use the term HUV Syndrome. However, there seems to be disagreement over its use. Some researchers use it when it’s more severe and involves the whole body (systemic), while other researchers use the term when there is no systemic involvement.
Causes of urticarial vasculitis
Researchers have not fully understood the cause of urticarial vasculitis.
It’s classified as an autoimmune disorder, which is when the body’s immune system mistakenly attacks the blood vessels. It's been noted that some families have a history of HUV.
Urticarial vasculitis has been linked to a few different conditions:
- Immunoglobulin disorders
- Inflammatory connective disorders like Systemic Lupus Erythematosus
- Leukemia and internal cancers
- Some infections like hepatitis B and hepatitis C
- Drug-related treatments such as the use of ACE inhibitors, penicillins, and sulfonamides
For about 50% of cases, the cause is unknown.
Diagnosing urticarial vasculitis
A skin biopsy is needed to confirm the diagnosis. A sample of skin is removed for testing, preferably from a new lesion that appeared less than 12 hours ago. It will be looked at under a microscope to check if there's damage to the small blood vessels in the middle layer of the skin (dermis). Blood tests can show the level of complement proteins to check if it’s HUV.
Treatments for urticarial vasculitis
There is no cure for urticarial vasculitis. The treatment approach depends on the symptoms and type of urticarial vasculitis. For those with normocomplementemic urticarial vasculitis (NUV), they typically have few other symptoms and the rash will often heal on its own.
For some cases which are resistant to corticosteroids, doctors may prescribe immunosuppressants, which slow down your body’s immune system. Some of these medications include azathioprine and methotrexate. This treatment may continue over several years.
For some severe cases, plasma exchange may be needed. This involves a machine that removes antibodies from the blood and then returns “cleaned” blood back to the body.
Skin Problems and Treatments Resources
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Clinical & Experimental Immunology: "An approach to the patient with urticaria."
DermNet New Zealand: "Urticarial vasculitis."
Genetic and Rare Diseases Information Center: "Hypocomplementemic Urticarial Vasculitis."
The Journal of Clinical and Aesthetic Dermatology: "Hypocomplementemic Urticarial Vasculitis Syndrome: A Case Report and Literature Review."
Maedica a Journal of Clinical Medicine: "Gastrointestinal Manifestations in Systemic Autoimmune Diseases."
Merck Manuals: "Innate Immunity."
Merck Manuals: "Swollen Lymph Nodes."
Skin Cancer Foundation: "Photosensitivity & Your Skin."
Vasculitis Foundation: "Urticarial Vasculitis."
Vasculitis UK: "Urticarial Vasculitis."