For some people, hives are not a short-lived nuisance but a condition that lingers for months or even years. Chronic spontaneous urticaria, or CSU, is defined as itchy hives that persist for at least six weeks. While individual welts usually fade within 24 hours, new ones often appear as older spots disappear, creating an almost daily cycle of flares.
Unlike acute hives, which are commonly triggered by food, medication or another clear allergen, CSU is usually not tied to an external cause. Evidence suggests most cases stem from an internal autoimmune response, where the immune system mistakenly activates cells under the skin.
This ongoing immune activity helps explain why avoiding specific foods or products rarely stops the outbreaks. About half of patients see symptoms resolve within six months, and roughly 80% reach remission within three years, though a small percentage experience symptoms for much longer.
Severity can vary widely. People with frequent flares, deeper swelling known as angioedema, or other autoimmune conditions may face a longer course. Elevated inflammatory markers have also been linked to more intense disease, though these findings show association rather than direct cause. While CSU is not typically lifelong and remission is common over time, persistent or severe swelling — especially involving the lips or throat — requires prompt medical evaluation.
SOURCE:
Health, February 13, 2026