Delayed pressure urticaria.

Delayed pressure urticaria is a mechanical urticaria in which pressure causes whealing. Delayed cutaneous erythema and edema occur in association with marked subcutaneous swelling after the application of a sustained pressure stimulus to the skin. The earliest reports and theories of the pathogenesis of delayed pressure urticaria are summarized.

Classification of anti-FcepsilonRI and anti-IgE autoantibodies in chronic idiopathic urticaria and correlation with disease severity.

Background: Circulating autoantibodies against FcepsilonRI, IgE, or both occur in approximately one third of patients with chronic idiopathic urticaria (CIU), but not all autoantibodies initiate histamine release.

Objective: We sought to classify patients with CIU into subsets on the basis of serum bioactivity and immunoreactivity and to examine the relationship between newly defined subtype and disease severity.

Methods: Sera from patients with CIU (n = 78), dermog-raphism (n = 15), and cholinergic urticaria (n = 10) and sera from healthy subjects (n = 39) were analyzed by means of Western blot analysis for anti-FcepsilonRI autoantibodies and for histamine release from basophils and dermal mast cells.

Antihistamines in urticaria and angioedema.

H1-antihistamines are the cornerstone of symptomatic treatment in acute and chronic urticaria, in which they not only relieve itching, but also reduce the number, size, and duration of urticarial lesions. Relief of whealing, flaring, and erythema may be incomplete as the vascular effects of histamine are mediated to its action at H2-receptors as well as at H1-receptors, and other vasoactive substances may also be involved. In randomized, prospective, placebo-controlled, double-blind studies, the new low-sedating H1-antihistamines have been found to be effective and safe in urticaria.