What is penicillin allergy?
Penicillin allergy is the most common drug allergy. About 10% of all people report having an allergic reaction to penicillin at some time in their lives. While many people who have a reaction to penicillin will be able to take it again later in life –sensitivity to the drug can decrease with time – others should not.
This is an important issue because penicillin can treat many serious problems. For some conditions, it may be the only effective option available. Penicillin has saved many lives over the years. Some people are understandably hesitant to take it because they or someone they know has had a bad reaction to it. Yet while caution is warranted, patients should not be so afraid of penicillin that they refuse to take it without learning more.
What should I do if I have a reaction to penicillin?
If you believe you are having a reaction to penicillin, or any medication you are taking, you should call the healthcare provider who prescribed it to you. (For extreme cases, call 911. You may need emergency treatment to stop the symptoms.)
The provider will usually ask the following:
- What symptoms you are having
- When you started taking the medication
- When the symptoms started to appear
- If you have stopped taking the medication
- How severe the symptoms are and if you have done anything to stop them, such as taking an allergy medication
- What other medications you are taking, including over-the-counter products
Try to give the most complete answers to these questions that you can.
What are the symptoms of a penicillin allergy?
Some penicillin allergies appear the first time a person takes the medication. For other people, the response appears the second time, after their immune system has had time to produce antibodies to it. (An antibody is a protein made by white blood cells that helps defend against invaders such as viruses.)
The most common symptoms of a penicillin allergy include:
- Skin rash or hives (raised pink areas of skin that are usually very itchy)
- General itching, which may come and go over hours
- Wheezing or other breathing problems
- Coughing
- Nasal congestion
- Swelling throughout the body
- Nausea and vomiting
- Tunnel vision
- Feeling dizzy or light-headed
- Fast or irregular heartbeat
The most dangerous reaction is anaphylaxis , which is a severe, life-threatening allergic reaction. Signs of anaphylaxis can include dangerously low blood pressure, wheezing, vomiting, tightness in the chest, diarrhea, swelling, and hives – often experienced all at once. Some people may lose consciousness when this happens, and go into shock.