Which conditions are changing?

Among the 58 countries that did report climate-associated effects, the pattern of disease change was consistent. Heat rashes increased in 81.0% of those countries, and inflammatory skin diseases — conditions such as eczema in which the immune system drives irritation and swelling — rose in 75.9%. Infectious skin diseases changed in 62.1% of countries, and half (50.0%) reported changes in vector-borne diseases, meaning illnesses spread by carriers such as mosquitoes and ticks.

"The most important finding from our study is that climate change is already associated with negative impacts on skin disease, and these effects disproportionately burden lower-income settings," said study author Dr. Esther Freeman. "We often think about the effects of extreme weather on heatstroke, cardiovascular problems and respiratory diseases, but the skin is our front line to climate change."

Why heat and rain matter for skin

The mechanisms, Freeman explained, are straightforward. "Higher temperatures and humidity can increase sweating and skin irritation, while heat, air pollution and other environmental exposures may trigger or worsen inflammation. Shifts in temperature and rainfall can also affect the habitats of mosquitoes, ticks and other disease vectors, potentially allowing them to survive in places where they were previously uncommon."

In other words, a warming world attacks the skin from several directions at once: directly through heat and humidity, indirectly through pollution and shifting ecosystems, and through the disruption caused by climate-related migration and extreme weather.

A compounding vulnerability

The authors point to a stark global inequality in the results. "Despite contributing the least to climate change, countries with fewer resources were more likely to report climate-related dermatological changes," they write. "This is especially alarming since these are often the same countries with the least capacity to adapt."

Many lower-income countries sit in regions already experiencing extreme heat, flooding, and shifting rainfall patterns. At the same time, they often face limited access to health care, dermatologists, medicines, and public health infrastructure. The result, the authors argue, is a compounding vulnerability: the greatest health risks coincide with health systems that have the fewest resources to prevent, identify, and treat disease.

What comes next

The researchers call for stronger surveillance, better education, and locally tailored adaptation strategies, particularly in resource-limited settings.

"We need to start treating skin health as part of climate-health preparedness," Freeman concluded. "This means strengthening surveillance so changes can be detected earlier, improving education and awareness among health care professionals and communities and developing adaptation strategies that reflect local climate exposures, disease patterns and health-system resources."

The study has limitations worth keeping in mind. It relies on country representatives' reports rather than direct clinical measurements, and in some regions — Africa most notably — uncertainty and sparse data may obscure the true scale of the problem. The findings, while striking, describe reported associations rather than proven cause and effect in every case. Even so, the message from 136 countries is consistent: climate change is not a future threat to skin health. It is already visible in clinics around the world, and the countries seeing the most change often have the least capacity to respond.