Urticaria (Chronic Hives)

Chronic spontaneous urticaria is a condition in which itchy raised welts, called hives or wheals, keep appearing for six weeks or longer with no outside trigger anyone can identify. Individual hives usually fade within 24 hours, but new ones keep forming somewhere else. Some people also get deeper swelling of the lips, eyelids, hands or feet, which is called angioedema.

What chronic hives are, and what they are not

They are usually not an allergy. Chronic spontaneous urticaria is described in the Canadian and international literature as an immune process involving mast cells in the skin, occurring without an identifiable outside trigger. That is why extensive allergy testing is generally not part of the standard assessment, and why searching for a food or product to eliminate often leads nowhere. The word spontaneous in the name carries that meaning.

The other thing worth saying plainly is that Canada does not measure how common this condition is here. Statistics Canada, the Public Health Agency of Canada, the Canadian Institute for Health Information and Health Canada publish no figure for it. The three Canadian sources that do quote a number are all repeating general-population estimates from international literature, and they do not agree with each other: one Canadian consensus review gives 0.5% to 1%, a Canadian patient organisation gives about 1%, and a 2025 Canadian journal review gives 1% to 3%. For that reason this page publishes an international range rather than a Canadian number.

Signs and symptoms

• Itchy raised welts that come and go, usually fading within 24 hours in any one spot
• New welts appearing in different places as older ones settle
• Welts that have been recurring for six weeks or longer
• Deeper swelling of the lips, eyelids, hands, feet or genitals in some people
• Itch or burning that is worse in the evening or at night
• Broken sleep and daytime tiredness
• No consistent food, medication or contact trigger that explains the pattern

How long it lasts varies. A 2024 review reports a mean or median duration of roughly one to four years, with symptoms persisting for at least three years in about two thirds of people.

What raises the risk

Some things cannot be changed:

• Autoimmune activity, since chronic spontaneous urticaria is described as an autoimmune, mast cell driven condition
• Sex, with roughly twice as many women as men affected according to the Canadian Skin Patient Alliance
• Age, with onset most often between 20 and 50, and fewer than 15% of cases beginning before age 20
• Coexisting autoimmune conditions, including thyroid autoimmunity

Others can often be worked on, usually with support from a health care team:

• Anti-inflammatory medicines of the nonsteroidal type, which some people find worsen hives and which can be reviewed with a clinician
• Heat, pressure on the skin, tight clothing and alcohol, which can aggravate hives that are already there
• Stress and sleep loss, which some people notice alongside flares

How chronic hives are diagnosed in Canada

Diagnosis is clinical. A Canadian Medical Association Journal review describes it as resting on history and skin examination showing spontaneously appearing wheals, angioedema, or both, present for more than six weeks, without systemic symptoms or bruising. Basic laboratory testing usually includes a complete blood count, C-reactive protein and erythrocyte sedimentation rate, to look for other explanations. Extensive allergy testing is generally not part of the assessment. Disease activity is tracked with a validated score, the Urticaria Activity Score over 7 days, and the same review links a score of 16 or more to referral to a dermatologist or allergist.

Treatment and day-to-day management

Clinical research for Urticaria (Chronic Hives) is enrolling. See the current studies ↓

Care in Canada is usually stepped: start with regular preventive medicine, then add or change if symptoms are not controlled. Depending on your situation and what matters to you, a health care team may discuss:

• Second-generation H1 antihistamines taken daily as preventive therapy, with escalation described in the Canadian and international literature
• Anti-IgE monoclonal antibody therapy, used when antihistamines at escalated dosing do not control symptoms
• Immunosuppressant therapy such as cyclosporine, described as an off-label option in the reviewed literature
• Newer biologic options under evaluation and in use in some settings, including agents targeting type 2 inflammation
• Referral to a dermatologist or allergist, which the Canadian Medical Association Journal review links to an Urticaria Activity Score of 16 or more over 7 days

What suits one person will not suit another. Which of these applies to you, if any, is a decision for you and your own clinician, and this page is not a recommendation about any of them.

When to talk to a doctor

• See a clinician if hives have been recurring for six weeks or longer, or if itching is disrupting your sleep, work or daily activities.
• Book an appointment if hives come with swelling of the lips, tongue, eyelids or face, so that swelling episodes can be assessed and a plan put in place.
• Call 911 or go to an emergency department for difficulty breathing, throat tightness, trouble swallowing, dizziness or fainting, or for hives that appear together with these symptoms, as this can indicate a severe allergic reaction.

Why clinical research matters for chronic hives

In most people the cause is still not established, there is no test that predicts who will respond to which treatment, and roughly two thirds of people have symptoms lasting at least three years. Canada has no prevalence, wait time or cost data of its own for this condition, which makes it hard to plan specialist access or to argue for it. Research now under way includes new mast cell targeted therapies such as BTK inhibitors and anti-KIT antibodies, further anti-IgE and type 2 targeted biologics, biomarkers to separate autoimmune subtypes, and studies of treatment response and remission over time.

Clinical studies are how those questions get answered, and Canadian participation is what would put Canadian numbers on the record. Taking part is voluntary, you give informed consent before anything begins, and you can stop at any time without affecting the care you get from your own doctor. Joining a study does not mean giving up your current treatment, and no one can tell in advance whether a study will help you personally.

Learn more from Canadian sources

• Canadian Skin Patient Alliance: chronic spontaneous urticaria
• Canadian Dermatology Association
• Canadian Medical Association Journal: managing chronic spontaneous urticaria
• Allergy, Asthma and Clinical Immunology: chronic urticaria, a Canadian perspective