Final answer:
Dermatitis is a common sign of an allergic reaction to penicillin. It manifests as a skin rash or inflammation, and is one option among others indicating allergic responses, such as hives and wheezing. Severe reactions include anaphylaxis, which is a medical emergency.
Step-by-step explanation:
Among the given options for signs of an allergic reaction to penicillin, Dermatitis would be a common symptom. Allergic reactions to penicillin and other drugs can trigger a variety of symptoms, including skin rashes or dermatitis, which refers to inflammation of the skin. Besides dermatitis, other symptoms indicating an allergic response might include itchy eyes, sneezing, hives, wheezing, and in severe cases, anaphylaxis. Anaphylaxis is a systemic and life-threatening reaction that requires immediate medical attention and can present as a dangerous drop in blood pressure, wheezing, shortness of breath, and swelling of the tongue and throat, which can lead to suffocation.