Why is acne decreasing in New Zealand?

A new study has found acne rates are going up everywhere - except New Zealand.

But before we go marvel at our clear, glowing skin in the mirror, let's pause and ask why? Data alone rarely tells the whole story.

What was the new study?

The study published this week in the British Journal of Dermatology aimed to unearth global and regional trends in acne diagnosis rates for those aged 10 to 24 years.

Researchers analysed data from 204 countries and territories that spanned 1990 to 2021 to determine how prevalent acne was and how bad it was. They also looked at the impacts of age, gender and socio-economic factors.

What did they find?

If you're in Germany, the news isn't great. It had the highest rates of reported acne. The UK was in the top ten, increasing from 7 percent of adolescents and young people in 1990 to almost 15 percent in 2021.

North African and Middle East nations saw the largest increase in acne rates over the three decades.

And New Zealand was singled out as the only country with decreasing rates. However, it was a small decrease, according to Dr Zhou Zhu, from Peking Union Medical College Hospital and the study's lead author.

"It is plausible that, as healthcare becomes more accessible in countries, reported acne rates increase," said Zhu. "This is unlikely to be the only factor though, as even in countries with good access to healthcare, cases have increased."

The data doesn't take into account those who are self-managing their acne without going to doctor or dermatologist.

Why are acne diagnoses decreasing in New Zealand?

We don't know, but Dr Louise Reiche from the NZ Dermatological Society has a few theories.

First, the more positive hypothesis: Reiche called New Zealand a world leader in accessibility for acne treatment.

The first-line treatment for severe acne is isotretinoin, the active ingredient in Oratane.

Since 2009, nurse practitioners and GPs in New Zealand have been able to prescribe Oratane that is subsidised by the government. Previously, dermatologists were the sole gatekeepers to subsidised Oratane.

This might mean "there is a reduced acne burden because we're treating it more effectively at an earlier stage of the disease," Reiche said.

Other countries, such as the UK and Australia, have not loosened their restriction over concerns about some nasty isotretinoin side effects that can include birth defects if someone takes isotretinoin while pregnant and suicidal thoughts. Females of child-bearing age should be on birth control before, after and during their isotretinoin acne treatment.

However, concerns about depression and mood swings are based on dated research.

"By far, the majority of people improve their mood because their skin and their self image has improved," Reiche said.

It's also possible that environmental factors in New Zealand could reduce actual incidences of acne and not just diagnosis.

"Getting outdoor exposure while being sun protected does improve acne. Having time in green and blue space does help and it helps not only psychologically but it also helps because exposure in those settings provides a favourable microbiome, which lessens your risk of acne," Reiche said.

Zhu, the researcher on the study, said lower pollution level in New Zealand could reduce the occurrence of acne. Eating less ultra processed foods and eating more fresh fruits and vegetales are other factors.

"Of course, further research is needed to confirm the specific reasons behind this trend," Zhu said.

On the flip side, New Zealand's lower rates of acne diagnosis might be because there is a chronic shortage of dermatologists and GPs, pushing some to self-manage their acne or do nothing at all.

"[The data] might simply be reflecting the fact that there is reduced access for patients with acne to get care," Reiche said.