Possible role of diet in delayed pressure urticaria--preliminary report.

Abstract Late cutaneous reactions preceded by an immediate wheal-and-flare reaction have been described after allergen skin testing, intradermal 4880 injection, and skin testing with heterologous antihuman IgE. We report the finding of delayed cutaneous reactions after prick food skin testing in a subgroup of five patients with delayed pressure urticaria. This subgroup is also defined by symptomatic clearing after fasting. We demonstrate a correlation of food challenge with skin test response in this same subgroup. Some patients who had previously required prednisone for control of urticaria were able to be managed without it while they were receiving the exclusion diet. In addition, their pressure symptoms and challenge disappeared while they were receiving the restricted diet. These findings suggest that an underlying food sensitivity may be an important precipitating factor in some patients with delayed pressure urticaria.