Pathophysiology of acute urticaria?
Urticaria (hives) is a vascular reaction of the skin marked by the transient appearance of smooth, slightly elevated papules or plaques (wheals) that are erythematous and that are often attended by severe pruritus. Individual lesions resolve without scarring in several hours. Most cases of urticaria are self-limited and of short duration; the eruption rarely lasts more than several days, it but may be recurrent over weeks. Chronic urticaria is defined as urticaria with recurrent episodes lasting longer than 6 weeks.
@lalaraj Urticaria results from the release of histamine, bradykinin, leukotriene C4, prostaglandin D2, and other vasoactive substances from mast cells and basophils in the dermis. These substances cause extravasation of plasma into the dermis, leading to the urticarial lesion. The intense pruritus of urticaria is a result of histamine released into the dermis. One study showed that D-dimer levels correlate with the severity of acute urticaria and may serve as a marker of disease severity. Individual lesions of acute urticaria can appear at different locations and fade without scarring, often in a matter of hours. The development of urticaria can be an isolated event without systemic reaction or it can be a prelude to the development of an anaphylactic reaction. Although urticaria results from transient extravasation of plasma into the dermis, angioedema is the subcutaneous extension of urticaria that results in deep swelling within subcutaneous/submucosal tissues and is associated with pain but not pruritus