Overview
Hypocomplementemic urticarial vasculitis (HUV), also known as McDuffie syndrome or urticarial vasculitis with hypocomplementemia, is a rare autoimmune disease where the immune system mistakenly attacks the body's own blood vessels. The name describes two key features: low levels of complement proteins in the blood (hypocomplementemia) and inflamed small blood vessels beneath the skin (vasculitis) that cause hives (urticaria). Unlike ordinary hives that come and go quickly, the hives in HUV tend to last more than 24 hours, often leave bruising or discoloration behind, and can be painful or burning rather than just itchy. HUV affects multiple parts of the body beyond the skin. It commonly involves the joints, eyes, kidneys, and lungs. Some people develop serious complications such as kidney inflammation (glomerulonephritis), chronic obstructive pulmonary disease (COPD), or eye inflammation (uveitis). The disease is closely linked to systemic lupus erythematosus (SLE) and shares many features with it. Many patients have antibodies against a complement protein called C1q, which is considered a hallmark of the disease. Treatment focuses on calming the overactive immune system and managing symptoms. Doctors may use anti-inflammatory medicines, antimalarial drugs like hydroxychloroquine, corticosteroids, and in more severe cases, stronger immune-suppressing medications. There is currently no cure, but many patients can achieve good control of their symptoms with the right treatment plan.
Also known as:
Key symptoms:
Recurring hives (raised, red, itchy or burning welts) that last more than 24 hoursHives that leave behind bruising or dark marks on the skinJoint pain and swellingEye inflammation (redness, pain, or vision changes)Kidney problems (blood or protein in urine)Shortness of breath or chronic lung diseaseAbdominal painFeverSwollen lymph nodesFatigue and general feeling of being unwellSwelling of the face, lips, or throat (angioedema)Low complement levels found on blood tests
Clinical phenotype terms (47)— hover any for plain English
Sporadic
Usually appears on its own, not inherited from a parent
Adult
Begins in adulthood (age 18 or older)
Treatments
No FDA-approved treatments are currently listed for Hypocomplementemic urticarial vasculitis.
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Rare Disease Specialist
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Hypocomplementemic urticarial vasculitis.
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Questions for your doctor
Bring these to your next appointment
- Q1.Which organs are currently affected in my case, and how will we monitor them over time?,What are the signs that my disease is getting worse, and when should I go to the emergency room?,What are the risks and benefits of the medications you are recommending for me?,Should I be tested for lupus or other autoimmune diseases given the overlap with HUV?,Are there any clinical trials or newer treatments I should know about?,How often do I need blood and urine tests to monitor my complement levels and kidney function?,Are there lifestyle changes — such as diet, sun avoidance, or stress management — that can help reduce flares?
Common questions about Hypocomplementemic urticarial vasculitis
What is Hypocomplementemic urticarial vasculitis?
Hypocomplementemic urticarial vasculitis (HUV), also known as McDuffie syndrome or urticarial vasculitis with hypocomplementemia, is a rare autoimmune disease where the immune system mistakenly attacks the body's own blood vessels. The name describes two key features: low levels of complement proteins in the blood (hypocomplementemia) and inflamed small blood vessels beneath the skin (vasculitis) that cause hives (urticaria). Unlike ordinary hives that come and go quickly, the hives in HUV tend to last more than 24 hours, often leave bruising or discoloration behind, and can be painful or burn
How is Hypocomplementemic urticarial vasculitis inherited?
Hypocomplementemic urticarial vasculitis follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Hypocomplementemic urticarial vasculitis typically begin?
Typical onset of Hypocomplementemic urticarial vasculitis is adult. Age of onset can vary across affected individuals.
Which specialists treat Hypocomplementemic urticarial vasculitis?
4 specialists and care centers treating Hypocomplementemic urticarial vasculitis are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.