CHRONIC URTICARIA – Characteristics

CHRONIC SPONTANEOUS URTICARIA (CSU)

This is the urticaria subtype whose onset does not have any flare-triggering factor. Patients keep seeking for a cause, but can never find one. About 60% of all chronic urticaria cases are spontaneous. It predominantly affects middle-age women, or 1-2% of the world population. There is no scientific explanation for its occurrence, because its causative mechanisms are not clearly known by medicine. Current scientific studies still report the potential of part of the spontaneous urticaria being an autoimmune disease; in this case, autoantibodies – or antibodies produced by our own bodies – are produced, therefore causing urticaria. To support this assumption, there is an observed association of that kind of urticaria with other autoimmune diseases, i.e., a CSU patient usually has other autoimmune diseases, with the most common one being the Hashimoto’s thyroiditis.

CHRONIC INDUCED URTICARIA

This is the type of urticaria resulting from an external triggering factor known as rubbing, pressure, vibration, localized heat, cold, increased body temperature, or by contact to water or other substances. Consistently to the specific cause, it will be named differently – for example, if caused by rubbing, it will be called dermographism; if it is caused by increased body temperature, it will be

called cholinergic urticaria. Some of them –caused by physical stimuli – were called physical urticaria in the past.

In induced urticaria, flares are short in duration, lasting less than 1 hour – except for delayed-pressure and contact urticaria, which can last longer.