Should amoxicillin (amoxicillin) be stopped in a patient who develops a rash?

From the Guidelines

If a patient develops a rash while taking amoxicillin, the medication should be stopped immediately if the rash is severe, widespread, or accompanied by other symptoms such as hives, itching, facial swelling, difficulty breathing, fever, or joint pain, as these could indicate a serious allergic reaction. Mild, non-itchy rashes that appear after several days of treatment may represent a non-allergic "amoxicillin rash," which is not dangerous and doesn't necessarily require stopping the medication 1. However, it is crucial to differentiate between a benign rash and a potentially life-threatening allergic reaction, such as Stevens-Johnson syndrome or anaphylaxis. The decision to stop amoxicillin due to a rash should be based on the severity and characteristics of the rash, as well as the patient's overall clinical presentation. Some key factors to consider when evaluating a rash in a patient taking amoxicillin include:

• The timing of the rash in relation to the start of antibiotic therapy
• The appearance and distribution of the rash
• The presence of other symptoms, such as fever, itching, or difficulty breathing
• The patient's medical history, including any previous allergies or adverse reactions to medications. If the medication is stopped due to a suspected allergic reaction, the patient should avoid all penicillin-class antibiotics in the future and inform healthcare providers about this allergy 1. Alternative antibiotics from different classes, such as macrolides (azithromycin), cephalosporins, or fluoroquinolones, may be prescribed instead, depending on the infection being treated. It is essential to note that the underlying infection still needs treatment, so patients should not simply stop the medication without consulting a healthcare provider about an alternative antibiotic. In general, the use of antibiotics should be guided by stringent diagnostic criteria and a careful assessment of the potential benefits and harms of treatment, as outlined in the principles of judicious antibiotic prescribing for upper respiratory tract infections in pediatrics 1.

From the FDA Drug Label

If an allergic reaction occurs, amoxicillin should be discontinued and appropriate therapy instituted. If patients develop skin rash they should be monitored closely, and amoxicillin discontinued if lesions progress.

Amoxicillin should be stopped in a patient who develops a rash, as it may be a sign of an allergic reaction or a severe cutaneous adverse reaction. The patient should be monitored closely, and if the lesions progress, amoxicillin should be discontinued and appropriate therapy instituted 2.

From the Research

Amoxicillin and Rash

• Amoxicillin can cause skin reactions in 5-10% of patients, with a higher frequency in those with viral illnesses, infectious mononucleosis, and lymphocytic leukemia 3.
• The most common types of skin reactions to ampicillin (a similar antibiotic to amoxicillin) are maculopapular rash and urticaria, with the maculopapular rash being a benign, nonallergic phenomenon 3.
• In cases of a maculopapular rash, ampicillin can be continued and administered again in the future, as this type of skin reaction resolves spontaneously in a few days without sequelae 3.

Serious Reactions

• However, amoxicillin can also trigger more severe reactions, such as Drug Rash Eosinophilia Systemic Symptoms (DRESS) syndrome, especially in patients taking other medications like sulfasalazine 4.
• DRESS syndrome is a systemic hypersensitivity reaction characterized by exfoliative dermatitis, maculopapular rash, lymphadenopathy, fever, eosinophilia, and involvement of internal organs, with a risk of fatal cases 4.
• Other severe reactions, such as IgA vasculitis, can also occur, especially in adult populations, and may require immediate discontinuation of amoxicillin and treatment with steroids 5.

Special Considerations

• In patients with infectious mononucleosis, the development of a rash after amoxicillin administration is not uncommon, and the rash usually resolves within days of discontinuing the antibiotic 6.
• In patients with systemic lupus erythematosus (SLE), amoxicillin can cause severe type IV hypersensitivity reactions, making it essential to monitor for signs of an allergic drug reaction 7.

Decision to Stop Amoxicillin

• The decision to stop amoxicillin due to a rash depends on the type and severity of the reaction, as well as the patient's medical history and concomitant medications 3, 4, 6, 5, 7.
• In cases of severe reactions, such as DRESS syndrome or IgA vasculitis, amoxicillin should be stopped immediately, while in cases of benign, nonallergic maculopapular rash, the antibiotic can often be continued 3, 4, 5.