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, Report informs referring to Daily Mail.

The complications caused by the pills, which are given to treat a number of common 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.

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 such as cephalexin 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, incuding trimethoprim, are used to treat UTIs, as well as inflammatory bowel disease, malaria and various skin, eye and vaginal infections.