Some years ago, a young man turned up at Dr Lee Cheng Chuan's clinic in Tan Tock Seng Hospital's Communicable Disease Centre.

Reduced to skin and bones by HIV - the human immunodeficiency virus that causes Aids - his body was covered in unsightly rashes.

Dr Lee, who heads the HIV programme at the hospital, prescribed some medication for him.

"He responded very well to treatment but then stopped coming and went back to his old state. The next time he came in, he had to be treated for the same problems," he says.

A little prodding revealed that the man could not afford the medication, but was too proud to approach a medical social worker for help.

"He said his mother gave him only $10 a day. He told me he just wanted to give up and die," says Dr Lee, 52. "I asked him what was it that he loved most, and he said he loved to surf the Internet but could not afford it."

The infectious diseases expert struck a bargain with his patient.

"I told him that if he agreed to see a social worker and get help, I would pay his Internet bill."

The unusual deal worked.

"He got so well that he found a job, and now even pays for his own medication," he says.

The incident reaffirmed Dr Lee's belief that thinking out of the box can sometimes change outcomes.

"I always remember what William Osler said," he says, referring to the famous Canadian pathologist dubbed the father of modern medicine. "He said, 'The good physician treats the disease; the great physician treats the patient who has the disease.'"

Of course, HIV, which Dr Lee has committed himself to fighting for the last two decades, is no ordinary disease.

First clinically observed in the United States in the early 1980s, it is usually transmitted through unprotected sex with an infected person, or when drug abusers share needles and syringes. If untreated, it can lead to progressive failure of the immune system and pave the way for various opportunistic and lethal infections and cancers to thrive.

While medication has turned it from a death sentence to a manageable chronic disease, there is no effective cure for the stigma surrounding it. Many people living with HIV (PLHIV) are shunned like pariahs, and discriminated against by family, friends and employers.

That is precisely why the senior consultant at Tan Tock Seng Hospital's Institute of Infectious Diseases and Epidemiology decided to specialise in HIV medicine after passing his examinations in internal medicine more than 20 years ago.

"I like to do things which are not popular. And I want to help marginalised and shunned communities," says Dr Lee, who received a Red Ribbon award for his outstanding contributions to clinical care and social support for PLHIV at the Singapore Aids Conference yesterday.

The diminutive man never set out to be a doctor. For as long as he could remember, he wanted to be a teacher.

"Ironically, becoming a doctor led me back to where I wanted to be: teaching," says Dr Lee, who is also an adjunct associate professor at Yong Loo Lin School of Medicine.

He spent his childhood in a kampung in Chai Chee. His late father, who ran a transport company, had four children with his first wife. When she died in an accident, he married her younger sister, who gave birth to Dr Lee.

Life in the kampung, he says, was idyllic. "I feel sad when I see children nowadays. Their whole world is the small frame that is their smartphone or computer. But there is a big world beyond that frame.

"I played with nature a lot. I caught fish, tadpoles, frogs, dragonflies and butterflies."

The former student of Sang Nila Utama Secondary and Temasek Junior College breezed through school, and had his heart set on becoming a teacher. He even signed up for a Public Service Commission (PSC) teaching scholarship after his A levels.

The plan got disrupted during his national service.

"Because I was small and weak, I was often ridiculed and at the receiving end of sarcastic and condescending remarks. I told myself, 'Maybe I should become someone of 'higher status' so that I won't be bullied in future,'" he says.

Laughing at his simplistic logic, he adds: "I was young, lah. So, I went to change my course even though I had no intention of becoming a doctor. I went into medicine for the wrong reasons. According to current criteria, I probably would not even have been selected."

It was a bad mistake, at least in the beginning. Many people he met after he signed up for medical school at the National University of Singapore - from nursing officers to practising doctors - told him that medical studies were difficult and that doctors had no life.

The negative messaging bulldozed his self-confidence, which was shaky to begin with.

For the first two years, he grappled with depression.

"I felt I was in the wrong course. I had to go to a psychologist and went to see my mentor about leaving the course. They encouraged me to leave but I did not have the courage," he says ruefully.

Fortunately, he snapped out of it.

"It got better. Now, I'm so glad I persisted."

After his housemanship and a short stint as a polyclinic doctor, he decided to do a master's degree in internal medicine, the speciality of diagnosing and treating adult diseases. Upon completing his studies in 1994, he decided to specialise in infectious diseases. It changed his life.

Dr David Allen, an American infectious diseases specialist who came to Singapore in the late 1980s to help the Health Ministry establish this field of study, was a big inspiration.

"He worked late, was very patient and went to every hospital to look at infections," he recalls.

By then, Dr Lee had become conversant with the scourge of HIV sweeping across the world.

"I realised there was a big gap for HIV medicine in Singapore. Nobody was doing it except for people like David Allen, Edmund Monteiro and Leo Yee Sin," he says, referring to the first generation of specialists who stepped forward to care for HIV patients in Singapore.

Dr Monteiro was the director of the CDC, while Associate Professor Leo is now the director of TTSH's Institute of Infectious Diseases and Epidemiology.

Dr Lee remembers the dark days of treating HIV then. There were no subsidies for HIV drugs, which were extremely expensive. Treatment options were limited, too.

Many PLHIV and their loved ones resorted to smuggling in generic anti-retroviral medication from Thailand, which cost a fraction of what they cost here. The Government introduced subsidies for HIV medication only in 2008.

In those dreary days, doctors could not recommend the best form of treatment; they could only prescribe medicine that their patients could afford or that was available in the country.

Dr Lee, who saw as many as 20 patients over a half-day session, said he and his colleagues did not even do viral load testing in those days because they were not available.

The tests measure HIV virus particles in a patient's blood, and help doctors determine treatment.

"We knew their viral loads were not suppressed but we did not have enough drugs and we had to keep recycling them. We were just treating infection after infection until we couldn't save them any more. We were so numb."

With a sigh, he says: "Some of my patients could have lived. When they first came to see me, they were so strong and healthy but because they had difficulty accessing drugs at that point in time, they faded away and died. I often asked myself if I did enough, and if they died an unnecessary death."

Treating the disease, he says, has exposed him to the whole spectrum of human behaviour. He recalls an elderly man in his 70s who visited his sick friend every day during the year that he was hospitalised because he had to be artificially fed.

"Even on weekends, I'd see him sitting by the bedside reading the newspapers. He knew all his friend's medications and when he had to take what," he says.

The duo, he adds, were not a gay couple. Both were married and had families. "When the sick man found out he had HIV, he wanted to kill himself. But his friend, whom he had once helped, promised to take care of him until the day he died, and he did," Dr Lee says.

In contrast, there were also patients who were abandoned by their families and left to die lonely deaths in shelters.

What he saw and experienced quickly turned Dr Lee into an advocate. Together with several colleagues, social workers and activists, he fought to make treatment accessible and affordable.

He joined the executive committee of Action For Aids and mooted the idea of a yearly Singapore Aids Conference in 1998. A firm believer in the idea of social medicine, he played a key role in getting volunteers to help PLHIV.

He also leads the TTSH HIV Volunteer Programme, and personally trains each volunteer. The wards with HIV patients now boast the largest number of volunteers throughout the hospital.

Once headstrong and impetuous, he has learnt to fight the HIV battle more strategically.

"You cannot have too much anger, people are not persuaded by anger. I'd rather go for a compromise and then work towards a solution."

The landscape today is also radically different from the era of programmed death, when Dr Lee first started work in HIV treatment.

With treatment, PLHIV can expect normal life expectancy today. One of his current patients was diagnosed in the mid-1980s. There are even drugs that can be taken before or after exposure to prevent HIV infection.

"In theory, there can be an end to Aids if everyone came forward and got tested and treated," Dr Lee says.

But the taboo and stigma PLHIV face prevent that from happening, he adds.

"Every patient is a victim, and every victim is innocent regardless of how or where he got the disease. We cannot judge a person just because he has the virus ," says Dr Lee, who is "single and not seeking".

"People need to understand that to remove the stigma and the discrimination. Those who have not made mistakes in matters of sex need to ask themselves if they have done so in other areas," he says.

A lot still needs to be done, he adds. The 2013 recipient of a National Healthcare Humanity Award says: "The keyword is acceptance. It is important because it helps to break the chain of infection. Only when there is acceptance will people come forward and get tested and treated."

Besides HIV, Dr Lee has been at the forefront in fighting other infectious diseases, like the Nipah virus in 1999. He was one of the first three doctors to treat Singapore's first Sars super-spreader.

For someone who nearly dropped out of medical school, he loves what he does now. "I don't believe in work-life balance," he says with a laugh. "My work is part of my life. I find great meaning in it."