Hypocomplementemic urticarial vasculitis

What it is

From: Orphanet

A rare immune complex-mediated small vessel vasculitis characterized by urticaria and hypocomplementemia (low C3, C4 and/or C1q), and usually associated with circulating anti-C1q autoantibodies. Arthritis, pulmonary disease, ocular inflammation are common systemic manifestations.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Complement deficiency · Very frequent (99-80%)

An immunodeficiency defined by the absent or suboptimal functioning of one of the complement system proteins.

Pruritus · Very frequent (99-80%)

Pruritus is an itch or a sensation that makes a person want to scratch. This term refers to an abnormally increased disposition to experience pruritus.

Skin rash · Very frequent (99-80%)

A red eruption of the skin.

Small vessel vasculitis · Very frequent (99-80%)

A type of vasculitis (inflammation of blood vessel walls) that affects blood vessels that are smaller than arteries, i.e., arterioles, venules, and capilllaries.

Abdominal pain · Frequent (79-30%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) and perceived to originate in the abdomen.

Angioedema · Frequent (79-30%)

Rapid swelling (edema) of the dermis, subcutaneous tissue, mucosa and submucosal tissues of the skin of the face, normally around the mouth, and the mucosa of the mouth and/or throat, as well as the tongue during a period of minutes to several hours. The swelling can also occur elsewhere, typically in the hands. Angioedema is similar to urticaria, but the swelling is subcutaneous rather than on the epidermis.

Arthritis · Frequent (79-30%)

Inflammation of a joint.

Autoimmunity · Frequent (79-30%)

The occurrence of an immune reaction against the organism's own cells or tissues.

Conjunctivitis · Frequent (79-30%)

Inflammation of the conjunctiva.

Cough · Frequent (79-30%)

A sudden, audible expulsion of air from the lungs through a partially closed glottis, preceded by inhalation.

Dyspnea · Frequent (79-30%)

Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale.

Episcleritis · Frequent (79-30%)

Inflammation of the episclera, a thin layer of tissue covering the white part (sclera) of the eye.

Glomerulopathy · Frequent (79-30%)

Inflammatory or noninflammatory diseases affecting the glomeruli of the nephron.

Hematuria · Frequent (79-30%)

The presence of blood in the urine. Hematuria may be gross hematuria (visible to the naked eye) or microscopic hematuria (detected by dipstick or microscopic examination of the urine).

Other findings in the same source

From: Orphanet

Additional reported features include Hemoptysis (Frequent (79-30%)); Inflammatory abnormality of the eye (Frequent (79-30%)); Nausea and vomiting (Frequent (79-30%)); Proteinuria (Frequent (79-30%)); Renal insufficiency (Frequent (79-30%)); Uveitis (Frequent (79-30%)); Irregular hyperpigmentation (Frequent (79-30%)); Abnormal heart valve morphology (Occasional (29-5%)); Airway obstruction (Occasional (29-5%)); Ascites (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adult; Childhood

Inheritance in the source

From: Orphanet

Autosomal recessive; Not applicable

Frequency and the population described

From: Orphanet

Point prevalence: Unknown; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing Hypocomplementemic urticarial vasculitis is Rheumatology, with a rheumatologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Are the findings inflammatory, structural or due to another mechanism?
• Is there evidence that other organs need assessment?
• How will function and any treatment-related risks be monitored?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Hypocomplementemic urticarial vasculitis. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.