Late cutaneous reactions in patients with delayed pressure urticaria.

Late cutaneous reactions ( LCRs ) have been described in patients after allergen skin testing, skin testing with heterologous anti-human IgE, autologous skin-blister fluid, and, variably, after 48/80 injection. We report our results of skin testing patients with delayed pressure urticaria ( DPU ), chronic urticaria, and normal volunteers with histamine and 48/80. All patients with DPU had LCRs after 48/80. No patients in either of the other groups developed LCRs . This may be a clue to pathogenic mechanisms involved in DPU .