Summary

Urticaria (Hives) is a common condition characterised by itchy wheals (raised, erythematous, oedematous lesions) that result from mast cell degranulation and histamine release in the superficial dermis. Individual wheals are typically fleeting (resolve within 24 hours) and intensely itchy (not painful). Urticaria is classified as Acute (less than 6 weeks, often allergic or viral) or Chronic (≥6 weeks, most commonly Chronic Spontaneous Urticaria [CSU], often autoimmune). Angioedema (deeper dermal/submucosal swelling) may accompany urticaria. First-line treatment is non-sedating H1 antihistamines (Cetirizine, Fexofenadine, Loratadine), which can be increased up to 4x licensed dose in chronic refractory cases. Omalizumab (Anti-IgE antibody) is highly effective for severe CSU. Always exclude Anaphylaxis in acute presentations with systemic symptoms. [1,2]

Clinical Pearls

Fleeting Wheals (Each less than 24h): If individual lesions last >24 hours and are painful or leave bruising, consider Urticarial Vasculitis – different condition requiring investigation.

Chronic = Usually Autoimmune (CSU): Chronic Spontaneous Urticaria is often due to autoantibodies against IgE receptor. No external trigger found.

Up to 4x Antihistamine Dose: Standard dose often insufficient. Guidelines endorse increasing up to 4x licensed dose before escalating therapy.

Omalizumab Works: Anti-IgE monoclonal antibody is highly effective for CSU refractory to antihistamines.

• Acute Urticaria: Usually self-limiting (Days to weeks).
• Chronic Spontaneous Urticaria (CSU): Variable. ~50% resolve within 1-3 years. Some persist for years.
• Omalizumab: Excellent response rates (~70-80%). Symptoms may return on stopping.

Key Guidelines

What is Urticaria (Hives)?

Urticaria (also called "Hives" or "Nettle Rash") is a condition where you get itchy, raised, red bumps on the skin (called "wheals"). They can appear anywhere on the body and usually come and go quickly – each bump usually lasts less than 24 hours.

What causes it?

In many cases, no specific cause is found. Sometimes it's triggered by an allergy (food, medication), an infection (like a cold), or a physical factor (cold, heat, pressure). In chronic cases (lasting more than 6 weeks), the immune system often mistakenly triggers the skin reaction without an external cause.

Is it serious?

Usually, urticaria is uncomfortable but not dangerous. However, if you have swelling of the lips, tongue, or throat, or difficulty breathing, this is an emergency (anaphylaxis) – call 999.

How is it treated?

The main treatment is antihistamine tablets (like Cetirizine or Fexofenadine). You may need to take a higher dose than usual. Most cases get better over time, but some people need specialist treatments like Omalizumab (an injection).

Common Exam Questions

1. Duration of Individual Wheal: "How long does each individual wheal last in typical urticaria?"
   • Answer: less than 24 hours.
2. Urticarial Vasculitis Clue: "What feature suggests Urticarial Vasculitis rather than simple Urticaria?"
   • Answer: Wheals lasting >24 hours, Painful (not just itchy), Leave bruising/Purpura.
3. First-Line Treatment: "First-line treatment for Chronic Spontaneous Urticaria?"
   • Answer: Non-sedating H1 Antihistamine (Cetirizine, Fexofenadine, Loratadine), up to 4x licensed dose if needed.
4. Third-Line Treatment: "Biologic therapy for refractory CSU?"
   • Answer: Omalizumab (Anti-IgE Monoclonal Antibody).

Viva Points

• 4x Dose Antihistamines: Explain this is guideline-endorsed, off-label use.
• Dermographism Test: Demonstrate/describe.

Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.