Allergies due to antibiotics differ from adverse reactions, such as stomach pain and diarrhea. An allergic reaction occurs because the immune system becomes over-sensitized and recognizes the antibiotic as foreign. Antibiotic allergies include penicillin, sulfa and tetracycline antibiotics. According to Physician's Desk Reference, true allergies from antibiotics cause characteristic symptoms, such as rashes, hives or raised itchy spots that appear for a few hours or less, swelling of the throat, tongue, lips and eyes, vomiting and anaphylaxis--very low blood pressure and difficulty breathing. Allergies can be very serious; notify your physician about any present or past reactions to antibiotics.
Penicillin
Penicillin belongs to a family of antibiotics called beta lactams and several types of penicillins are regularly prescribed for common bacterial infections. Penicillin allergies are common and someone who is allergic to this antibiotic, will be allergic to all types of penicillin. According to Roland Solensky M.D. a physician and writer at Uptodate.com, approximately 10 percent of people report an allergy to physician, while most individuals that report reactions to penicillin have adverse reactions but not true allergies. In addition, only about 20 percent of individuals that experience an initial allergic reaction to penicillin will still have an allergy 10 years later, if they are not exposed to this antibiotic again.
Sulfa Antibiotics
Sulfa antibiotics can cause an allergic response in individual's with immune systems that overreact to the drug, aAccording to WrongDiagnosis.com. Sulfa or sulfonamide antibiotics were the first antibiotics used medicinally, but are not as commonly used today. Some sulfa antibiotics still in use include Septra, Bactrim and Pediazole. Approximately 3 percent of individuals have an allergic reaction to these types of antibiotics and people with compromised immune system due to illness such as AIDS are at higher risk. Symptoms of sulfa antibiotic allergies include skin rashes, aching joints, swollen lymph nodes and sun sensitivity.
Tetracyclines
Tetracyclines are antibiotics prescribed to treat bacterial infections, such as persistent acne, cholera, pneumonia and typhus. It is in the same family as the commonly prescribed antibiotics doxycycline and minocycline. Individuals with at true allergy to tetracycline will be allergic to all antibiotics in this family. Serious allergic reactions to these antibiotics include symptoms, such as skin rash, itching or hives, yellowing of eyes, difficulty breathing, vomiting, throat sores and severe joint pain. Treatment may be needed if these symptoms are experienced. A study published in the medical journal "Clinical and Experimental Allergy," revealed that some individuals who do not normally have tetracycline allergies may experience allergic reactions to a commercial preparation made out of a combination of three tetracyclines.
