Ask a GW Expert: What Are the Implications of Global Warming for Dermatology

Authored by:

Vishal Patel is an expert at treating skin cancer. Demand for his services increases every year; he took some time from his busy schedule at GW's School of Medicine and Health Sciences to tell us about whether global warming can help explain why.

Skin cancer rates are increasing for a number of reasons. One is because we have an aging population. People are living longer and being more active, and also taking more medicines. Because medications have potential side effects or interactions with the immune system, that's a relative push. As we get older, our immune system is weaker.

The other big piece is that people are generally healthier, living longer, and they go to the doctor for a variety of other reasons, especially to the dermatologist. And so we are looking more for things, and then we find things that maybe would not have been found had patients not been as healthy and died of another comorbidity.

Combine our aging population with the fact of our sun-loving lifestyle. UV rays from the sun are a form of radiation, a carcinogen. And so, just like any other carcinogens, like cigarette smoking, anything in excess can be detrimental. Patients who seek out sun exposure, whether they're a beach bum, just doing a lot of outdoor activities or simply wanting to be tanned, that increases the rate of the DNA damage that is going to come up later. We've had decades of that with the '70s, '80s and '90s, so we're seeing the results now.

There's been a lot of push in the health and longevity movement around exercises like tennis, pickleball, walking and hiking in general. We're seeing all these activities increase as people try to live healthier lives.

Global warming itself is not causing skin cancer, but there is a complex interplay with the rising temperatures. Skin cancers are caused by UV radiation. And the UV index, when it's high, is more damaging. But the UV index can be high on cloudy days; it can be high during the winter; it can be high on summer days. When holes open up in the ozone layer, that's another way that UV radiation could get in and cause damage.

So, there are environmental aspects that I'm sure are going to exacerbate the UV intensity, but the big piece is that when the temperatures rise, we have behavioral modifications. For example, if it's warmer in the winter or in the spring, people tend to be more active and spend more time outdoors. And if you're getting more UV radiation exposure, and historically you did not because it was colder or you were inside, that's going to increase your cumulative exposure over your lifetime. In the summer, if it's warmer or more humid and you're being very sun-savvy and health-conscious and wearing sunscreen, sunscreen only lasts for about 90 to 120 minutes if you're active, sweating, moving around.

The ambient temperature and humidity is rising due to global warming. Our tolerance of the heat, sweating if we're applying sunscreen, or wearing more revealing clothing to cool down, all puts us at risk if the sunscreen is not reapplied and we are in a sunny climate. It's a combination of factors.

Apart from skin cancer, there's a lot of research being done about how climate change is going to impact eczema rates, things where your skin biome can be impacted and fungal types of infections that tend to grow in warmer environments.

Your ethnic makeup, melanin concentration, skin and genetics play a role, and also just inherent risk and how you're taking care of yourself.

As seasons change, as climate changes, just be thoughtful around what your strategies are. That can be sun avoidance in high UV days or areas during peak hours, doing activities early in the morning, later in the afternoon or just modifying your attire. There's a lot of UV-protective clothing that is comfortable as well. So, there's more than one way to be sun-protective and not just have to avoid the sun completely or slather yourself in sunscreen 24/7.