Urticaria is a common cutaneous
disease characterized by recurrent and
transient wheals and
pruritus, sometimes accompanied
angioedema. The
classification of
urticaria is based on the duration of the
disease and whether extrinsic triggers are identified or not. Acute
urticaria is usually occurred by specific causes, such as
drug,
food, and
infection, etc. Therefore, acute
urticaria can be remitted within 6 weeks just by avoiding the exposure to the causes. However,
chronic urticaria defined as repeatedly occurred itchy wheals and/or
angioedema for at least 6 weeks, has a significant effect on
patients'
quality of life.
Chronic inducible urticaria can be triggered by various physical stimuli including dermographism, delayed
pressure,
cold,
heat,
cholinergic stimuli,
sunlight, and
exercise.
Chronic spontaneous urticaria (CSU) is diagnosed when no specific extrinsic cause is identified in the
patients. CSU due to autoimmune mechanism accounts for 30–50%, autologous
serum skin test and anti-
thyroid autoantibody can be evaluated. However, various physical stimuli, emotional or physical stress,
drugs, particularly
aspirin and non-steroidal anti-inflammatory
drugs can exacerbate
urticaria in 30–75% of
patients with CSU. Allergic
diseases and
autoimmune diseases are more common in CSU
patients than in general
populations. To assess the severity of
urticaria and to adjust
treatment step,
urticaria activity score over 7 days, calculated by the number of wheals and the severity of
pruritus, is recommended by recent international guidelines.