Antibiotics quickly became the mainstay treatment for bacterial infection since they were first discovered in 1928. Although recent research and development has increased the safety and efficiency of this drug category, antibiotics are basically foreign matter that is introduced into your body to fight other foreign matter causing illness and disease. Allergic reactions to antibiotics develop when the body mistakenly identifies these proteins as an allergen.
According to Mayo Clinic, penicillin is the most common drug allergy experienced. The University of Virginia Health Systems also lists antibiotics which are in the penicillin family, sufa drugs and cephalosporins as those that are commonly associated with an allergic rash reaction. Less commonly, many of the antibiotics available today can also cause an allergic reaction. A rash reaction with the first dose is possible, but more commonly a rash will appear after several doses of the medication.
According to the Medical College of Georgia, two different types of rashes associated with allergic reactions to antibiotics can occur. The first are hives. These are raised welts on the skin that can be white or red and will be itchy. They can pop up for a few hours and then disappear. The second type of rash reaction is pinpoint, red and itchy which loses the red color when pressed. An allergic skin rash will not be in straight lines or localized like a contact dermatitis but rather will be more generalized across the body. This rash usually involves the face, trunk and extremities.
According to Dr. William Sears, an author and pediatrician who operates the website Ask Dr. Sears, the medication should be stopped and the physician who prescribed the antibiotic should be contacted. Some skin rashes are harmless while others are more serious and require immediate medical attention. Only the physician who has knowledge of underlying medical conditions and the primary medical issue should determine the risk of continuing the antibiotic versus the benefit of eradicating the infection. Diphenhydramine is an antihistamine available over the counter that physicians may recommend to help stop the itching. Cool baths with colloidal oatmeal or cool wet compresses can also help relieve the itching.
According to Mayo Clinic, the most serious allergic reaction to antibiotics is an anaphylactic response. This reaction often starts with hives and rapidly moves into a life-threatening situation. Anaphylaxis will present with difficulty breathing, wheezing, swelling of the throat or tongue, dizziness, loss of consciousness, rapid or weak pulse. This is a medical emergency which requires immediate care.
According to Mayo Clinic physicians, the best way to avoid an allergic reaction is to stop taking the responsible antibiotic. Unless there is an anaphylactic response, the prognosis is very good. Once the antibiotic has been metabolized from the body the rash response should disappear without any ill effects. For some infections, the use of penicillin is necessary for treatment. Those who have an allergy to penicillin may undergo a desensitization process in the hospital if the physician determines that penicillin is absolutely necessary. It can take one or two days to complete and does not work in all cases.