NEW DELHI : Ringworm, a common skin disease among Indians, is slowly turning resistant to drugs, making it difficult to cure. A recent study by the central government-run Ram Manohar Lohia Hospital has shown that the fungus that causes the disease has been undergoing mutation and growing stronger due to excessive use of an oral drug, itraconazole.

Approximately 40 different species can cause ringworm, a contagious infection that occurs on cells in the outer layer of the skin. The infection can spread by direct, skin-to-skin contact with an infected person. It is usually an itchy, circular rash with clearer skin in the middle.

“This is the first such study where we have explored the potential reasons behind the failure of drugs to treat ringworm. We found that there is mutations in enzymes of the fungus and it’s getting resistant to all drugs,” said Dr Kabir Sardana, professor of dermatology at RML Hospital and one of the authors of the study.

According to experts, the drug of choice globally for treating the infection is terbinafine, which is still given in other countries. “In India, we found seven years ago that it is failing. Here, mostly itraconazole is used, which is not recommended in other countries,” Dr Sardana pointed out.

A major reason for it failure is its extreme usage. “Itraconazole is the highest selling drug and also highly misused. If this drug gets resistant, nothing is left for the treatment of ringworm infection in India. This is the last oral drug that can be used for the treatment,” he added.

Dr Sardana said when the same drug is used over and over against a fungus, it aggravates efflux pump in the affected cells. “It acts as a defence mechanism to remove the drug from its body. If this continues to happen repeatedly, slowly the action of the drug becomes non-functional.” Itraconazole tablets are not just given for ringworm but also for fungal infections in the lungs, blastomycosis (Gilchrist’s disease) or histoplasmosis (Darling’s disease).

Dr Sardana pointed out that the drug was being prescribed in wrong doses for wrong durations, making it ineffective. “Even for treating ringworm, the drug is prescribed at 400mg for three-four months. The ideal dose is 100mg for four-six weeks. The fungus is getting the opportunity to evade the drug,” he said.