An instructor is developing a plan for a class of nursing students on various skin disorders. When describing urticaria, what would the instructor include?

A. It is a type IV hypersensitivity reaction: Urticaria is typically a type I hypersensitivity reaction mediated by IgE, not a delayed type IV reaction. Type IV reactions involve T-cell–mediated responses, such as contact dermatitis, rather than immediate histamine-mediated reactions. B. Histamine release leads to vasodilation: Urticaria results from mast cell degranulation and histamine release, which increase vascular permeability and cause local vasodilation. This leads to the characteristic erythema, swelling, and itching associated with hives. C. Wheals appear first followed by erythema: In urticaria, erythema and wheals usually appear simultaneously as a result of histamine-induced vasodilation and plasma leakage into the dermis. There is no distinct sequence of wheals followed by erythema. D. The nonpruritic rash blanches with pressure: Urticarial lesions are typically pruritic (itchy), not nonpruritic, and may blanch under pressure due to transient vasodilation. Pruritus is a hallmark symptom distinguishing urticaria from other rashes.