Understanding Urticaria: A Comprehensive Guide

What Is Urticaria?

Urticaria is the medical term for hives: raised, itchy welts that appear on the skin, ranging from a few millimetres to several centimetres across. They are typically red or skin-coloured. Importantly, each individual welt usually fades within 24 hours, even if new ones keep appearing elsewhere. This can confuse patients, as the rash seems to move around the body, disappearing in one place and reappearing in another.

Urticaria is often accompanied by angioedema — deeper swelling that most commonly affects the lips, eyelids, tongue, or hands. Angioedema can feel tight, tender, and alarming, though in most cases, it resolves within 72 hours. Around 40% of people with chronic urticaria experience both conditions.

The underlying mechanism involves mast cells — specialised immune cells present throughout the skin — releasing histamine and other inflammatory chemicals. The trigger for this release is where things get complicated.

Acute vs Chronic Urticaria

Urticaria is broadly divided into acute (lasting less than six weeks) and chronic (lasting six weeks or more). Acute urticaria is very common and often has an identifiable cause — a reaction to food, a drug such as ibuprofen or aspirin, an insect sting, or a viral infection. It's unpleasant, but it typically resolves on its own or with antihistamines.

Chronic urticaria is a different matter. It affects roughly 0.5–1% of the population at any given time, which sounds small but translates to hundreds of thousands of people across the UK. It is roughly twice as common in women as in men, and the average duration is two to five years — though in around one in five patients, it persists beyond five years.

Chronic Spontaneous Urticaria: When There Is No Obvious Cause

The most common form of chronic urticaria is chronic spontaneous urticaria (CSU) — where hives appear without any identifiable or reproducible external trigger. No food, no drug, no allergen. For many patients, this is the most frustrating aspect of the condition. They often spend months eliminating foods, changing washing powder, and scrutinising ingredient labels, often to no avail.

Research suggests that in many cases of CSU, the immune system is essentially reacting against itself. Up to half of patients appear to have an underlying autoimmune mechanism, where the body produces antibodies that directly activate mast cells. This is why CSU is sometimes associated with autoimmune thyroid conditions.

It is also worth noting that stress doesn't cause CSU, but it can reliably worsen it — creating a difficult cycle. The impact on quality of life from CSU is substantial. More than 40% of patients report significantly impaired daily function, and research consistently shows the burden is comparable to conditions like psoriasis. Anxiety is reported in up to 40% of patients with chronic urticaria, and depression affects a significant proportion. This isn't incidental — the constant uncertainty, disrupted sleep, and visible nature of the condition take a real toll.

Inducible Urticaria: When There Is a Trigger

Not all chronic urticaria is spontaneous. Chronic inducible urticaria (CIndU) refers to hives triggered by specific physical stimuli — cold temperatures, heat, pressure on the skin, exercise, sunlight, or even water.

Cold urticaria, for example, causes hives when skin is exposed to cold air or water. In severe cases, swimming in cold water can provoke a systemic reaction. Dermographism — sometimes called "skin writing" — produces wheals wherever the skin is firmly stroked.

These inducible forms can often be identified by simple provocation tests during a specialist consultation.

The Treatment Pathway

First-line treatment for urticaria is a non-sedating antihistamine. If standard doses aren't sufficient, guidance supports increasing the dose up to four times the standard amount. Many patients find adequate relief at this stage, but a meaningful proportion do not. For those individuals, the next steps are where specialist input becomes particularly important.

For patients whose chronic spontaneous urticaria is not controlled despite antihistamines, omalizumab (brand name Xolair) is the recommended next step according to both NICE guidance (TA339) and international allergy guidelines. Omalizumab is a biological therapy — a monoclonal antibody — that works by binding to free IgE in the bloodstream. By reducing IgE levels, it effectively quiets mast cell activity and breaks the cycle of histamine release.

It is given as a subcutaneous injection every four weeks. NICE approved it specifically for chronic spontaneous urticaria in adults and young people aged 12 and over whose symptoms are not adequately controlled by antihistamines. Real-world UK data shows meaningful, often dramatic, symptom improvement for many patients who had previously struggled to find relief.

A biosimilar version, Omlyclo, has demonstrated equivalent efficacy to omalizumab in clinical trials and is also available for patients seeking this treatment.

It's worth noting that omalizumab for CSU is available privately. We see patients from the UK, the United States, and elsewhere who specifically seek it out for ongoing management of their condition. If you have been told your hives are untreatable or simply left on antihistamines that aren't working well enough, it is worth knowing that more options exist.

When Should You See a Specialist?

A GP can manage straightforward acute urticaria. However, a referral to — or direct appointment with — an allergy specialist is worth considering if:

• Hives have been present for more than six weeks

• Antihistamines aren't providing adequate control

• There is associated angioedema (swelling)

• The cause isn't clear despite initial assessment

• Symptoms are significantly affecting sleep, work, or quality of life

  
  

A specialist can offer a more detailed assessment to help determine whether the urticaria may have an autoimmune basis and discuss the full range of treatment options — including biological therapy.

Ready to Get a Clearer Picture of What's Driving Your Urticaria (hives)?

At The London Allergy Clinic, our consultant allergists see adults with urticaria — both acute and chronic — at our clinics in Marylebone, Fitzrovia, and High Barnet.

We offer specialist assessment, testing where appropriate, and access to omalizumab and Omlyclo for patients with chronic spontaneous urticaria that hasn't responded to antihistamines.

Book a consultation or contact us by phone or WhatsApp, Mon–Sat 9am–7pm: 0207 637 9711

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