Much has been discovered in recent years regarding the histopathology of chronic idiopathic urticaria. What three major types of cells may be encountered in increased numbers in these biopsies?

The characteristic histopathologic finding of nonvasculitic chronic urticaria is a subtle to modest perivascular and interstitial infiltrate. There are increased numbers of lymphocytes. Mast cells are increased some 10-fold, while there is a fourfold increase in mononuclear cells. There is increased histamine in blisters suctioned from chronic urticaria patients. Although eosinophils are often not prominent, increased deposition of the major basic protein of the eosinophil is present in the tissue in 50% of patients, indicating eosinophil involvement in the inflammatory process, although only a fraction of these had evidence of eosinophilic accumulation.

Elias J, Boss E, Kaplan AP: Studies of the cellular infiltrate of chronic idiopathic urticaria: prominence of T lymphocytes, monocytes, and mast cells, J Allergy Clin Immunol 78:914–918, 1986.


Sabroe RA, Poon E, Orchard GE, et al: Cutaneous inflammatory cell infiltrate in chronic idiopathic urticaria: comparison of patients with and without anti-FceRI or anti-IgE autoantibodies, J Allergy Clin Immunol 103:484–493, 1999.

 
Ying S, Kikuchi Y, Meng Q, et al: TH1/TH2 cytokines and inflammatory cells in skin biopsy specimens from patients with chronic idiopathic urticaria: comparison with allergen-induced late phase cutaneous reaction, J Allergy Clin Immunol 109:694–700, 2002.