SINGAPORE - In primary school, children teased him by calling him names like "vampire" and "botak".

Raffles Institution student Loh Yih Hang has no sweat glands and minimal salivary glands. The 18-year-old looks older than he is, with no hair and missing teeth.

"I've looked more or less like this since young," he said.

"Back then I was a bit uncomfortable with it and I didn't really know how to deal with it... but my parents told me not to care about what other people say about me," said Yih Hang.

On Friday, he collected his A-level results from the school, where he was a student for six years.

He scored straight As in all his subjects - H2 physics, chemistry, mathematics and geography, as well as H1 General Paper and project work.

Yih Hang hopes to study computer science in a local or overseas university.

Diagnosed at birth with hypohidrotic ectodermal dysplasia, he is also susceptible to heatstroke as the condition makes him unable to sweat and expel heat.

He has developed a "thick skin" to block nasty comments about his appearance, he said.

"I also made friends who were accepting of my condition, all the way from primary school to now."

Today, he is unfazed by the looks he get, and has come to accept that his medical condition is part of who he is. He even jokes about it.

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"Sometimes my friends talk about wanting to change their hair colour, and I'd say I wish I can dye my hair too," he said.

His outlook changed in his upper primary years, when he was able to share with people about his condition.

"I'm actually quite happy when people ask me about my medical condition rather than just stare," he added.

He tries to stay in the shade most of the time, and keeps a water bottle by his side in case he needs to drink more.

"If I get very hot, I would pour some water over my head to cool down," he said.

"I will always have this medical condition. It's not something that can be cured.

"I have become more confident in sharing my life story, my challenges and interacting with people, even strangers."

In school, he joined physical education lessons as often as he could, and swam every week to keep fit.

He was part of RI's prefectorial board in his first four years, and joined the student council in his junior college years.

He also volunteered weekly at Meet-the-People sessions in the Toa Payoh-Novena area.

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"I try to do everything to the best of my abilities, and participate as much as I can," he said, adding that his business-owner parents shaped him to be who he is today.

He has two younger brothers.

"Anyone who has a medical condition has his own set of challenges which no one will be able to fully understand," he said.

But he added that this condition has taught him tackle challenges, even in his studies, and take problems in his stride.

"If life is predictable, it would cease to be life and become boring," he said.

"If we see all these challenges as ways to make life more interesting, it will be easier to overcome them."