The spectrum of acquired and familial cold-induced urticaria/urticaria-like syndromes.

Acquired cold urticaria syndromes represent one of the more common forms of physical urticaria. The syndromes are heterogenous, and a diagnostic classification is presented to facilitate collation for future studies. Acquired cold urticaria represents an excellent reproducible in vivo model to investigate the mechanisms of urticaria. The discussion includes clinical manifestations, laboratory features, pathogenesis, and management of these disorders. A description of familial types, particularly familial cold auto-inflammatory syndrome (FCAS) that is manifested by cold-evoked signs and symptoms of chronic inflammation, is included. FCAS historically has been included with acquired cold urticaria, even though the exanthem of FCAS is maculopapular caused by leukocytic infiltration. FCAS has become an important investigative syndrome, as it represents a reproducible in vivo model of chronic inflammation.