Allergies are versatile. They can affect your nose, eyes, throat, lungs, stomach, skin and nervous system. Allergy symptoms occur when your body’s immune system overreacts to substances in your environment.

People take antibiotics when there is infection, which is caused by bacteria. Antibiotics can cause allergic reactions. The diagnosis of antibiotic allergy is rarely clear-cut. It is often not clear whether the symptoms are due to the patient’s underlying condition or to the treatment. Common side effects of antibiotics includes upset stomach, diarrhea, and in women, vaginal yeast infections.

Many people have had allergic reactions to antibiotics. Several different types of rashes can appear while people are taking antibiotics. Rash is the main symptom, it is often difficult to determine whether the cause was the antibiotic, or the infection that prompted its use. Rashes involve hives (raised, intensely itchy spots that come and go over hours.

Some people are allergic to certain antibiotics. Penicillin is the most common cause of serious allergic drug reactions in children as in adults. Anaphylaxis is a sudden life threatening allergic reaction and usually includes swelling of the throat, inability to breathe, and low blood pressure.