URTICARIA and angioedema are common disorders. Although the specific cause of these disorders frequently is not known, certain underlying diseases and physical stimuli have been shown to produce these conditions and need to be evaluated.
Viral infections such as hepatitis B and infectious mononucleosis (IM) may be associated with urticaria. In some patients, cryoprecipitates have been demonstrated1 in which the presence of viral particles, antibodies, and complement components suggests a pathogenic role for immune complexes and complement activation.
Physical stimuli such as cold exposure may produce urticaria on exposed body surfaces of affected persons. The precise mechanisms by which cold temperatures produce these symptoms is unknown but may involve IgE antibody,2 cryofibrinogens,3 cold hemolysins,3 various chemical mediators,4 and cryoglobulins that are capable of complement activation.5
Although IM has been associated with cryoprecipitates6 and, to a lesser extent, cryoprecipitates have been associated with cold urticaria,