Can amoxicillin trigger allergies?

Amoxicillin is one of the drugs included in the beta-lactam antibiotic family and widely used for bacterial infections. Since it is affordable than the other antibiotics, it is generally prescribed to manage ailments such as middle ear infections, strep throat, dental infections, gonorrhea as well as upper or lower respiratory tract infections.

Why allergies develop?

An allergic reaction to amoxicillin is not considered hereditary but attained by individuals who are subjected to the drug at some point while under medical treatment. Those who are highly sensitive to the penicillin group are not assured to end up with a reaction to amoxicillin.

Individuals with HIV/AIDS, women and those diagnosed with cystic fibrosis face a higher likelihood to end up with an allergic reaction to the drug.


The reactions might start as a mild form such as rash and eventually progress to a severe one.

What happens during a mild allergic reaction to amoxicillin?

A delayed hypersensitivity reaction to amoxicillin and other drugs included in the penicillin family is considered rare.

The reactions might start as a mild form such as rash and eventually progress to a severe one. The usual allergic reactions include diarrhea, stomach upset and even vomiting.

Severe allergic reactions

Allergic rashes might develop on any part of the body, but the rash generally arises first on the arms, chest or legs. Take note that the rash may or might not itch.

Swelling is also another common reaction and might arise on the tongue and even threaten to impede the airways. The feet and hands might also become swollen. These reactions may or might not be accompanied by fever.

Anaphylaxis is the most severe reaction which involves difficulty breathing and arrhythmias. This allergic response might arise right away or develop during treatment. Prompt medical care is vital for this severe reaction.


The doctor will instruct the individual to stop taking amoxicillin once an allergic response occurs. The minor reactions such as rashes and hives are managed with over-the-counter drugs. As for severe rashes, oral corticosteroids are typically given.

In extreme instances, the doctor might inject corticosteroids. The treatment for anaphylaxis requires a shot of epinephrine in the emergency department along with monitoring of the blood pressure and breathing. Some require emergency care along with injections to alleviate the allergic hives.

More Information / Disclaimer

The information posted on this page on allergies to amoxicillin is for learning purposes only. Learn to recognize the indications by taking a standard first aid course with Saskatoon First Aid.


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