Dermatographism is characterized by which of the following?

Dermatographism is a type of physical urticaria, which is a condition that occurs when the skin is stroked or scratched, leading to localized swelling and hives in the affected area. The characteristic feature of dermatographism is that it triggers urticaria (hives) in response to mechanical pressure or minor trauma to the skin.

When the skin is stimulated, it causes mast cells to release histamine and other chemicals, resulting in localized inflammation and redness. This can appear as raised welts or wheals on the skin that correspond to the area that was scratched or pressed, which is often transient and resolves quickly after the stimulus is removed.

The other options do not accurately describe dermatographism. The presence of blisters is not typical of dermatographism; rather, the reaction is primarily hives. Severe systemic reactions, such as anaphylaxis, are not associated with dermatographism, as this condition is generally localized and not life-threatening. Chronic pain from skin inflammation is also not a hallmark of dermatographism, which primarily manifests as itching and wheals rather than persistent pain. Therefore, localized urticaria due to pressure accurately captures the essence of dermatographism.