Hives (Urticaria): Causes, Symptoms, Treatment, and When to Seek Care

Hives (urticaria) are raised, itchy wheals (welts) that can appear anywhere on the body. They range from a few millimeters to several centimeters, often with a pale center and red flare. Individual lesions typically last <24 hours, but new ones may appear for days or weeks.

Common Triggers

• Allergic: Foods (nuts, shellfish, eggs), medications (penicillin, NSAIDs), insect stings, latex.
• Physical: Pressure, cold, heat, sunlight, vibration, exercise (cholinergic urticaria).
• Infections: Viral (common in children), bacterial, parasitic.
• Autoimmune: Chronic spontaneous urticaria (CSU) often has autoantibodies against FcεRI or IgE.
• Idiopathic: No identifiable trigger (common in chronic urticaria >6 weeks).

Management

1. Avoid known triggers.
2. Second-generation H1 antihistamines (cetirizine, loratadine, fexofenadine) – first-line; can be dosed up to 4× standard dose for CSU.
3. Short-course oral corticosteroids (prednisone) for severe acute flares.
4. Omalizumab (anti-IgE) for refractory CSU.
5. Cool compresses, loose clothing, fragrance-free moisturizers for symptom relief.

Red Flags – Seek Immediate Care

• Difficulty breathing, wheezing, stridor
• Swelling of lips, tongue, throat (angioedema)
• Dizziness, fainting, abdominal pain, vomiting
• Hives persisting >24 hours individually, leaving bruising, or with joint pain/fever (possible urticarial vasculitis)

If hives last >6 weeks (chronic urticaria), consult an allergist/immunologist or dermatologist for systematic evaluation.