Penicillin allergy: which skin manifestation is most typical?

• A. The rash will not blanch.
• B. The rash will be fine and papular.
• C. There will be large, splotchy, nonpruritic areas.
• D. There will be hives.

Answer: (D)

Urticaria, or hives, is the most typical skin manifestation of penicillin allergy. These are itchy, raised wheals that often appear soon after exposure and blanch (turn pale) when pressed. The reaction stems from histamine release causing temporary swelling in the superficial skin, producing the characteristic wheals. While other skin patterns—non-blanching rashes, fine papular rashes, or large nonpruritic splotchy patches—can occur with various drug reactions, they’re not the classic presentation of an immediate penicillin allergy.