Skin Rash
An allergic reaction to penicillins may cause a skin rash that is often itchy and uncomfortable. This is the most common symptom, appearing as hives or bumps on the skin.
Breathing Difficulty
The person may face difficulty in breathing due to an allergic reaction to penicillins. This can range from mild shortness of breath or wheezing to severe difficulty breathing and a feeling of tightness in the chest.
Swelling
Swelling or edema can occur, particularly in the face, lips, tongue, or throat. This can result in difficulty swallowing or breathing, and is a serious symptom needing immediate medical attention.
Anaphylaxis
In severe cases, penicillin allergy can result in anaphylaxis, a life-threatening reaction that can cause a rapid, weak pulse; nausea and vomiting; loss of consciousness; and can interfere with breathing and heart function.
Fever
Some people may develop a fever as a result of an allergic reaction to penicillins. This is a sign that the body is trying to fight off an invader and can be accompanied by other systemic symptoms.
Joint Pain
Joints may become inflamed and painful as a result of an allergic reaction to penicillins. This can range from mild discomfort to severe pain that can interfere with daily activity.