Cephalexin is a cephalosporin antibiotic, and it is structurally related to penicillin. Because of this structural similarity, there is a risk of cross-reactivity between cephalosporins like cephalexin and penicillin. If you are allergic to penicillin, there is a possibility that you may also be allergic to cephalosporins.
If you take cephalexin while having a penicillin allergy, you may experience an allergic reaction. The allergic reaction can range from mild to severe and may include symptoms such as:
- Skin rashes or hives
- Itching or redness
- Swelling of the face, lips, tongue, or throat (angioedema)
- Difficulty breathing
- Wheezing
- Nausea and vomiting
- Abdominal pain
- Diarrhea
In severe cases, an allergic reaction can lead to anaphylaxis, a life-threatening condition that requires immediate medical attention. Anaphylaxis can cause a rapid drop in blood pressure, difficulty breathing, and loss of consciousness.
If you suspect or know that you have a penicillin allergy, it is essential to inform your healthcare provider before taking any medications, including cephalexin. Your healthcare provider may recommend alternative antibiotics that are not related to penicillin or perform an allergy test to determine the extent of your allergy.
Always follow your healthcare provider's advice and avoid self-medicating or taking any medications without proper medical supervision, especially if you have known allergies. If you experience any signs of an allergic reaction while taking cephalexin or any other medication, seek immediate medical attention.