Antibiotics prescribed to thousands of British patients can cause life-threatening skin rash, scientists find

Two types of commonly prescribed antibiotics can cause unsightly, painful rashes that can lead to deadly sepsis if untreated. 

The complications caused by the pills, which are given to treat a number of infections including UTIs and pneumonia, can lead to death in between 20 to 40 per cent of cases, according to a new 20-year study. 

Writing in the journal JAMA Network, experts behind the research have urged doctors to use lower risk alternatives. 

For the study, doctors at Sunnybrook Health Sciences Centre in Canada looked at more than 100,000 patients over the age of 66 who were prescribed oral antibiotics and studied harmful effects of the medications. 

Drug rashes – also known as severe cutaneous adverse drug reactions (cADRs) – are rare but life-threatening delayed reactions to certain medications

Over the 20 year study period, they found 20 per cent of the patient group visited the hospital for severe skin rashes, also known as cutaneous adverse drug reactions (cADRs).

The rashes can appear immediately after taking a medication, or weeks later, and are often caused by an allergic reaction.

Symptoms usually affect the skin — causing extreme red, scaly patches all over the body, but can trigger a dangerous overreaction of the immune system if untreated. 

On rare occasions, this results in sepsis — where the immune system attacks itself, leading to multiple organ failure and, sometimes, death.  

 The Canadian researchers found that the antibiotics that were most likely to ilicit this reaction were cephalosporins and sulfonamides – or ‘sulfa drugs’.

As well as penicillin, cephalosporins are among the most commonly prescribed antibiotics — used to treat pneumonia, meningitis, sepsis and UTIs. 

The antibiotic is also often given to children who are allergic to penicillin to treat ear infections. 

Sulfa drugs are used to treat UTIs, as well as inflammatory bowel disease, malaria and various skin, eye and vaginal infections. 

‘While rare, these severe drug reactions can be life-threatening,’ said David Juurlink, a staff internist and head of the Division of Clinical Pharmacology and Toxicology at Sunnybrook Health Sciences Centre.

‘Patients should be aware of rash, fever, and other symptoms, which can start weeks after a prescription has been started and even after the course of antibiotics has stopped.

‘It’s also one more reason why antibiotics should be prescribed only when they’re truly needed.’

All antibiotics can cause drug rashes —  as can antiseizure and antigout medications and even over-the-counter medications like NSAIDs. 

And while some patients have severe reactions, the majority of drug rashes are treatable.   

‘The good news is that most patients who visited the hospital with these reactions were discharged without being admitted, so that should be reassuring to providers and patients,’ says Erika Lee, an allergist and a trainee with ICES and Temerty Medicine’s Eliot Phillipson Clinician-Scientist Training Program.

‘However, of those who were admitted to hospital with the most severe reactions, twenty percent were treated in the ICU, and five percent of hospitalized patients died, which underscores the need for careful prescribing practices.’