Inducible urticaria or angioedema

**Definition:** The inducible or physical urticarias are a heterogeneous subgroup of urticarias in which pruritic weals, angioedema or both are triggered reproducibly by specific external physical stimuli. The onset of wealing is characteristically rapid with resolution within an hour. The exception is delayed pressure urticaria where weals take longer to develop and resolve. Individual susceptibility to a physical urticaria may be short-lived or may last for years.