What is chronic spontaneous urticaria?

Chronic spontaneous urticaria (CSU), often called chronic idiopathic urticaria (CIU), is the name for a certain kind of skin condition.[1] The name of the condition itself tells you about what it is:[1] 

• Chronic means something that lasts for a long time, or something that happens again and again.

• Spontaneous/ Idiopathic means something that happens spontaneously and has no known cause.

• Urticaria refers to raised hives (wheals) that usually have a red ring around them. These hives appear and disappear in less than 24 hours, and are often associated with itching or burning sensations.

Urticaria can be acute for example following exposure to a medication or a viral infection. Acute urticaria usually resolves in less than 6 weeks. [1]