Case Study: Rash Associated With Methadone Use

There have now been multiple reports of a similar rash among methadone users in Sydney, but many cases may have gone unreported. The cause, which remains unknown, is under investigation by the New South Wales Department of Health.

In October this year, a middle-aged man was referred to a hospital in south-east Sydney with a 14-day history of fever and a painful, red, swollen lower right leg, consistent with cellulitis Two days before the onset of the leg symptoms, he had noticed a non-itchy rash, which started on his legs and feet and spread to his abdomen and arms. The rash was accompanied by swelling and then peeling of his hands and feet.

The patient, a former intravenous heroin-user, had been in a methadone program for the previous eight years. He denied recreational drug use or sharing or injecting the oral methadone. Medications included daily methadone syrup and a range of other prescriptions, including relief for the rash and mild nausea.

After extensive tests, the cause of the original rash remained unknown. The cellulitis of the patient's right leg was successfully treated with antibiotics. He was discharged from hospital after four days with a range of medications to treat symptoms.

"We are aware of other patients with a similar rash, oedema and peeling of the hands and feet, all taking methadone," said Dr Annabelle Donaldson, Immunology and Infectious Diseases, St George Hospital, Sydney, and co-author of the report.

"We believe that all affected patients were taking the same brand and formulation of methadone. Most cases have been mild, and close contacts have not been affected.

"All patients appear to have continued using methadone from their usual dispensing clinic, and the rash has resolved over several weeks.

The authors believe other illicit drugs, including cannabis, are unlikely to be the cause, saying methadone is the most likely culprit for the outbreak, but that further investigation is needed.

"We need to consider the brand and batch of methadone used, storage, dose, mixing of batches in the dispensing pump, and other solutions included in the preparation to increase palatability.

"Pharmacists often mix batches of methadone and are not required to record the batch number dispensed to each patient, which makes tracing difficult.

"Methadone clinics, pharmacists, dermatologists, general practitioners and emergency medicine staff need to be aware of the possibility of these reactions," Dr Donaldson said.

A copy of the article will also be available from midday on Sunday 5 December 2004 on the MJA website (www.mja.com.au).

The Medical Journal of Australia is a publication of the Australian Medical Association.

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