Too many antibiotics are being taken for too long to treat severe acne. A U.S. study warns of the risk of antibiotic resistance, especially given that more effective treatments exist.

Acne is generally treated externally in the form of a gel or cream. Antibiotics are only used when this fails. As a last-resort treatment, dermatologists turn to isotretinoin, a drug derived from vitamin A which is anti-inflammatory and effective against severe acne. Its brand name is Roaccutane.

Around 4 per cent of Americans are said to have severe acne.

Researchers in dermatology at New York University Langone Medical Center in the U.S. have shown that doctors prescribe acne sufferers antibiotics that are often ineffective and are taken for too long.

The team analyzed the records of 137 patients aged over 12 who were treated for severe acne between 2005 and 2014. All of them were initially put on antibiotics for an average of 11 months, before their doctors recognized that they were ineffective and prescribed treatments containing isotretinoin.

The researchers observed that there was an average of nearly six months between the date the isotretinoin treatments were prescribed, and when they were first taken. The side effects (risk of birth defects, depression, etc.) could have been the reason for these "delays", the researchers noted.

Researchers noted that concerns about side effects and state restrictions (preventing the use of isotretinoin treatments during pregnancy) were a factor in extending antibiotic treatment.

According to Seth Orlow, one of the study's main authors, doctors and patients have become too complacent about the overuse of antibiotics and the subsequent danger of increasing antibiotic resistance.

He explained that the problem is exacerbated when patients change doctor or health plan, as most doctors switch antibiotics if one turns out to be ineffective. However, current guidelines on this matter recommend restricting antibiotic treatment to a maximum of two or three months for each class of drug, and six months as a whole, until significant improvement can be seen.

Orlow suggested that doctors speak to their patients about isotretinoin as a treatment as soon as possible. He concluded that "acne remains the number one reason for young people to visit a dermatologist and there are no other medications as effective as isotretinoin in treating severe cases of the skin condition."

The study was published in the Journal of the American Academy of Dermatology.