<unk>  <unk>  is defined as frequent (daily, or near daily) itching and wheals  for 6 weeks or more in the absence of any known cause.  The incidence is approximately 0.5% of the population.
Chronic idiopathic urticaria
Chronic cold urticaria
Dermatographic urticaria
Cholinergic urticaria
Pemphigus vulgaris
Atopic dermatitis
Pemphigus
Pemphigus foliaceus