The most common medication to treat ear infections are penicillin-class drugs. Of these, amoxicillin, alone or in combination with clavulinic acid, is the most commonly prescribed drug. Patients may have a variety of reactions to amoxicillin and other penicillin-class drugs. Penicillins belong to a type of drug known as known as beta-lactams. The reactions may range from skin rashes to life-threatening allergic reactions. Patients with allergies should alert their doctor about their reaction; if necessary, an alternative antibiotic can be prescribed. The treatment decision is largely based on the type of allergic reaction a patient has.
Minor Allergic Reaction
Minor beta-lactam reactions are not due to the drug itself but to the products that form when the antibiotic is broken down by the liver. Typical symptoms of a minor penicillin reaction are skin rashes and fever. The rash due to penicillin may take the form of hives or may be a flat, blotchy rash that slowly spreads over several days. These kinds of reactions may be irritating, but they are never dangerous.
Major Allergic Reactions
More serious penicillin reactions may cause hives, itchy skin and wheezing. Patients may also have angio-edema, which is a swelling in the face, lips and tongue. Beta-lactam antibiotics can also cause a life-threatening reaction called anaphylaxis. This can lead to breathlessness, a fall in blood pressure, dizziness or even loss of consciousness; these penicillin reactions are rare; it is estimated they occur in about 1 in every 5,000 drug exposures.
Determining Pencillin Risk
Patients who have an allergy to penicillin or any other beta-lactam antibiotic, such as amoxicillin, ampicillin or any cephalosporin drugs, should alert their doctor before getting a prescription. Cases of penicillin allergy can be diagnosed by doing a skin test in which a small amount of penicillin drug is injected into the skin. The presence of skin redness and swelling at the site is an indication of an allergic response.
Penicillin Alternatives
According to "Nelson's Pediatrics," otitis media should be treated with antibiotics. If patients have a history of a minor penicillin reaction, they are usually treated with cephalosporin antibiotics such as cefdinir, cefuroxime or cefpodoxime. While cephalosporins are also beta-lactams, they are not considered to be penicillins. People with severe penicillin reactions, however, should not be treated with these agents as there is a 10 percent risk of cross-reaction between these two classes of drugs. For these patients, physicians use alternative antibiotics such as azithromycin or clarithromycin. These antibiotics have no risk of cross reaction with amoxicillin.
References
- "Rang & Dale's Pharmacology"; Humphrey P. Rang et al.; 2007
- Uptodate.com: Patient Information: Allergy to Penicillin and Related Antibiotics; Roland Solensky
- Mayo Clinic: Penicillin Allergy
- "Brunner and Suddarth's Textbook of Medical-Surgical Nursing"; Lillian Sholtis Brunner et al.; 2009
- "Mayo Clinic Proceedings"; Diagnosis and Management of Penicillin Allergy; M.A. Park; March 2005
- "Nelson Textbook of Pediatrics"; Dr. Robert M. Kliegman, et al.; 2008
