The planet and the patient
How dermatologists confront the impact of climate change on patients.
Feature
By Jan Bowers, December 1, 2020
While political and economic concerns have permeated the debate around climate change, particularly in the United States, medical issues are increasingly coming to the forefront. According to the Centers for Disease Control and Prevention (CDC), “climate change, together with other natural and human-made health stressors, influences human health and disease in numerous ways” and will both intensify existing health threats and generate new ones. An infographic on the CDC’s web page shows the health effects resulting from higher levels of carbon dioxide in the atmosphere, which lead to increasing temperatures, more extreme weather, and rising sea levels.
A recent survey by the International Society of Dermatology (ISD) indicates that dermatologists as a group aren’t climate change skeptics. Conducted online by the ISD’s Climate Change Committee, the survey was sent to ISD members worldwide. Respondents included dermatologists (87.4%), dermatology residents (12%), and other health care providers (0.6%). The results showed that 95.6% recognize climate change is occurring, and 88.6% indicated that climate change will impact the incidence of skin diseases in their areas (Int J Dermatol. 2020;59(9):e322-e325). Approximately one-third reported unusual skin conditions in their communities that they believed could be related to climate change, “including common and atypical infections, UV- or heat-related disease, and inflammatory dermatoses.”
Sarah Coates, MD, a fellow in pediatric dermatology at the University of California, San Francisco, is one of six members of the ISD Climate Change Committee and a member of the AAD’s Climate Change and Environmental Affairs Expert Resource Group (ERG). She said she was a little surprised at the percentage of respondents who reported specific skin effects of climate change in their area. Overall, she said, the survey results “illustrate that dermatologists worldwide care about this issue and think that it’s a medical issue, not a political one.”
DermWorld spoke with Dr. Coates and three other dermatologists who are leading the effort to educate their colleagues about the urgency of the threat that climate change poses to public health, how it may be affecting their patients, and how they can become involved.
Disease vectors expand their territory
Vector-borne diseases, including arboviruses, comprise one of the most serious health threats linked to climate change. They are also among the most insidious, because “[disorders] we learned as tropical dermatology when we were in medical school and residency are now no longer just affecting the tropics, but rather can be present in the United States, in our subtropical areas and even traditionally colder areas,” said Mark D. P. Davis, MD, chair of dermatology at Mayo Clinic in Rochester, Minnesota, and co-chair of the ISD Committee on Climate Change. Previously, dermatologists would have been on the lookout for diseases such as dengue fever and chikungunya in patients returning from a tropical area, “but now, as the planet warms, particularly in hot places like Florida, we have to think: Is it possible that this person with the fever could have something more exotic than our usual differential diagnosis for this area?”
“Now, as the planet warms, particularly in hot places like Florida, we have to think: Is it possible that this person with the fever could have something more exotic than our usual differential diagnosis for this area.”
Dengue, chikungunya, and Zika viruses are spread by the Aedes aegypti mosquito, according to a review article on the effects of climate change on skin disease in North America (J Am Acad Dermatol. 2016;75(1):140-7). Dengue and chikungunya are the “big ones” that dermatologists should be on the lookout for, said Markus Boos, MD, PhD, assistant professor of dermatology at Seattle Children’s Hospital. “They have very striking dermatologic manifestations: Bright red rashes with a pattern described as ‘islands in a sea of fire,’ as well as bone and joint pain. For me — as a pediatric dermatologist — chikungunya has a very distinct sign in neonates, where they have striking hyperpigmentation, often in the central facial area. I’ve yet to see it myself, as it hasn’t yet made it to Seattle, but I’m aware that these things could be coming my way.” Dr. Coates noted that Ae. aegypti mosquitoes are showing an ability to survive at increasingly higher latitudes. “Most cases of dengue that are diagnosed in the United States are in returning travelers, but there are a few [locally transmitted cases] every year in Florida and Texas, and that will become increasingly true as temperatures stay hotter year round and the mosquitos don’t die off in the winter.”
According to the CDC, in 2019 there were 16 cases of dengue in Florida and two in Texas. As of late September, one state, Florida, reported 55 cases of dengue in 2020.
Leishmaniasis is another example of a tropical disease creeping north, said Misha Rosenbach, MD, associate professor of dermatology at the Hospital of the University of Pennsylvania, a co-author of the JAAD review article. Both cutaneous and visceral leishmaniasis are caused by infection with Leishmania parasites through the bite of Phlebotominae sand flies. “About 10 years ago, mathematical models predicted that it would become endemic in the U.S. based on how the climate was changing, and now there have been cases reported in Texas [and Oklahoma].” Because leishmaniasis is still widely considered a “foreign disease, you’re going to see delays in diagnosis. And although it’s a skin disease, it can also cause destructive disease in the mucosa, the liver, and other organs. Diagnosing it requires special testing at the CDC.”
Just as Ae. aegypti mosquitos and sand flies begin their encroachment into the continental U.S., the blacklegged tick, or deer tick (Ixodes scalpularis), long established in the northeast, continues its inexorable march outward, bringing Lyme disease to nearly every state and into Canada. The tick can infect its host with the Borrelia burgdorferi bacterium; the first visible sign of Lyme disease is often erythema migrans, frequently (but not always) in a ‘bull’s-eye’ pattern. “The habitat of the tick has definitely expanded due to climate change — you can watch the march northward as things are warming,” said Dr. Rosenbach. “The deer move, the tick moves, and then there are kids with Lyme disease both earlier and later in the year because the warming climate has extended the season, and with cases in new geographic areas. This is a particular issue in patients with darker skin, because it’s harder to recognize Lyme disease in those patients.”
Lyme disease cases reported to the CDC have tripled in the U.S. since the late 1990s. The agency attributes the increase in part to climate change, but also implicates factors like suburban development, which brings people in closer contact with deer and other tick hosts such as mice and chipmunks. A research article exploring the impact of climate change on the incidence of Lyme disease (Can J Infec Dis Med Microbiol. doi: 10.1155/2018/5719081) examined the relationship between temperature and humidity and the reported incidence of Lyme disease in 15 states, finding “sizable impacts of temperature” on disease incidence.
After the disaster
Sudden disasters like wildfires, hurricanes, and floods draw the world’s attention as they’re occurring, but their health effects — including those that involve the skin — can linger long after the TV cameras have left. “A warming world means more extreme weather events,” said Misha Rosenbach, MD. “Cutaneous issues are the most common health issue that follows extreme weather. Tornados, hurricanes, floods, and fires are all devastating on their own, but you don’t necessarily think of all the skin and soft tissue infections that happen in the aftermath — all the contact dermatitis or rashes or allergic reactions.”
Among weather disasters, flooding is one of the leading causes of skin disorders, said Markus Boos, MD, PhD. “We know that after Hurricane Katrina there was severe storm surge, and in the week following Katrina there were about 20 to 25 cases of Vibrio in the area,” he noted. “That’s because there was all this stagnant, warm water that people were wading through.” Existing open wounds, in addition to those caused by flying, floating, or submerged debris, can invite a host of other infectious organisms.
A comprehensive article exploring the dermatologic consequences of flooding cited “ordinary bacterial pathogens such as pyogenic Staphylococcus and Streptococcus” as frequent causes of skin infections after flooding, as well as infections from less common bacteria such as Vibrio vulnificus and Aeromonas hydrophila (Am J Clin Dermatol. 2015; 16: 399-424). In addition, the authors noted, “both typical and atypical fungal infections are increased in the flooding disaster scenario, such as dermatophytosis, chromoblastomycosis, blastomycosis, and mucormycosis.” Mark D. P. Davis, MD, pointed out that prolonged exposure to water can also lead to the “trench foot type of problems that we used to see in the First World War. When people stand in wet environments, they can end up with lacerated skin that breaks down and results in ulcers.”
Displacement caused by weather disasters can force people into crowded shelters, where skin disorders run rampant. “We have a massive homeless crisis here in San Francisco, and we see a lot of scabies, body lice, and streptococcal skin infections here,” said Sarah Coates, MD. “After a wildfire or flood, many people have nowhere to go. They may not have access to laundry services to help them avoid getting things like body lice, so they’re vulnerable to being caught in the same vicious cycle as our homeless populations are.” Dr. Boos cited tinea corporis and staph infections as disorders that can spread among people living in close quarters.
Dr. Coates, who has worked extensively in East Africa, also pointed to the nutritional aspects of environmental catastrophes. “When patients don’t have access to food because their crops are destroyed — like what just happened in Iowa — they’re at risk of developing severe nutritional deficiencies, and we will see a lot of skin manifestations. That might not be as true right now for dermatologists in the United States, but it’s something that’s going to be very important worldwide and that might lead to great political instability.”
Recognizing new infections
In addition to vector-borne diseases, dermatologists may start to see viral, fungal, and bacterial infections that were not previously endemic to their area. “Vibrio is the perfect infectious organism to talk about in the context of climate change because it’s temperature-sensitive and will only grow in places where it’s warm enough,” said Dr. Boos. “We used to see this in places like the mid- to southern-Atlantic states, and now it’s creeping further and further up the east coast. There was an outbreak in Alaska, and some reported in Scandinavian waters — areas that should have been cold enough to keep it from growing.” Infections from the bacterium Vibrio vulnificus can occur as a result of consuming contaminated shellfish or directly through the skin via an open wound (see "After the disaster" above). “When it’s skin inoculation, it can cause purpura, bullae, and ulcers, and vibrio septicemia is life-threatening,” said Dr. Boos. “A couple of summers ago, it appeared in the popular press as cases of ‘flesh-eating bacteria’ in Florida; many of those cases turned out to be Vibrio.” The JAAD review article notes that “even small changes in peak water temperature have been correlated with local hospital admissions for V. vulnificus-associated wound infections, cellulitis, and sepsis.”
“Vibrio is the perfect infectious organism to talk about in the context of climate change because it’s temperature-sensitive and will only grow in places where it’s warm enough.”
Infections from atypical mycobacteria (a group that excludes the bacteria that cause tuberculosis and leprosy) are seen particularly in immunosuppressed individuals, said Dr. Davis. “They often present with skin nodules that spread along the lymphatic drainage of a limb,” he noted. “We also see it in association with tattooing when the water of a tattoo parlor is infected. So, it can be associated with water exposure, among other things. But again, because of the warming planet, all of these atypical, unusual infections seem to be becoming more prevalent. What the exact mechanism of that is, we’re not entirely sure.”
Dr. Davis said he is also seeing more hand-foot-and-mouth disease (HFM) outbreaks throughout the U.S., a disorder caused by an enterovirus. “Not only are we seeing it more frequently, but it’s presenting in an atypical way,” he remarked. “We used to see it just confined to hand, foot, and mouth, but now we’re seeing kids with more and more extensive disease, and it’s presenting in adults too. Not that there’s a lot we can do about it, apart from supportive management, but I think it’s important to recognize it.” Dr. Rosenbach indicates that there is evidence that HFM spreads better in warmer, more humid environments, and in China there are studies linking increased spread and cases in adults to climate change. Dr. Boos noted that in most patients it’s uncomfortable at worst, “but it can have really serious sequelae in individual patients.” According to the CDC, in very rare cases, an HFM patient will develop viral meningitis, encephalitis, or paralysis.
Two dermatologists cited coccidioidomycosis, also known as Valley Fever, as another fungal disease to watch as it expands beyond its traditional range. “It thrives in arid conditions out here in [California’s] Central Valley and in Arizona,” said Dr. Coates. “Its range is now expanding northward, and we suspect that that’s because with fewer winter freezes, the organism can survive. You might not know you have it until you’re immunosuppressed after a transplant, for example, and all of a sudden you have massive pneumonia and potentially skin sequelae.” About 100,000 people are infected each year through inhalation of the Coccidioides immitis spores, according to the American Thoracic Society; more than 60% never develop symptoms or mistake their symptoms for a mild flu. Skin manifestations may include “red-purple papules, nodules and plaques, pustules, ulcers, and abscesses, and widespread morbilliform eruptions,” said Dr. Boos. “Outside the southwest, it’s probably not high on most people’s differential diagnosis, but that’s where climate change is so important: It’s changing where we expect to see these disorders. If you live in Washington state, you need to be mindful of cocci — not because someday you might live in Los Angeles, but because it’s in your backyard right now.”
How dermatologists can address climate change
In the view of dermatologists at the forefront of the issue, climate change action begins with individual patients and practices. “Watch out for the so-called tropical diseases that we used to think were only in travelers,” said Dr. Davis. “Because the climate is basically turning tropical to various degrees all across the world, and in the U.S. in particular.” Dr. Boos agreed, emphasizing that “self-education is so important, because if you’re not thinking about it, you’re going to miss it.” In addition to learning about which disorders pose the greatest threat and watching for symptoms, dermatologists can track the spread of several vector-borne and infectious diseases through the CDC website, which also provides a list of which disorders should be reported to public health officials.
A great deal remains unknown or poorly understood about how climate change affects health, and “that can engender a feeling of frustration or hopelessness,” said Dr. Rosenbach. “But we should feel empowered. We can make personal choices, beginning with eco-friendly practices in our offices and homes. The AAD has a partnership with My Green Doctor, which shows how physicians can make environmentally friendly changes that actually save them money.” My Green Doctor uses a “green team” model to guide a practice through the implementation of sustainable practices. For dermatologists creating a new building to house their practice, DermWorld published a Q&A with two Arkansas dermatologists who built the state’s first LEED-certified medical clinic.
For larger institutions, Dr. Rosenbach points to Practice Greenhealth as an organization whose sustainability solutions have saved “hundreds of thousands to millions of dollars per health care system that has adopted their metrics. There are a lot of examples that are personalized to your specific practice, so maybe if you do a lot of surgery you could switch from disposable tools to reusable tools, or if you have a large office you could benefit by switching energy providers.” Dr. Boos said he and some colleagues at Seattle Children’s wrote letters to the faculty and administration and “basically agitated. And our hospital just committed to a carbon neutral goal by 2025, which is the right direction. Even if you’re just one person, you can find your group of like-minded people. As physicians, we’re important to the bigger institutions we work for, and we should leverage that to make change.”
Dermatologists who want to learn more about the effects of climate change or become involved in advocacy can start with the Academy’s climate change ERG and the ISD’s climate change committee. The ERG held a two-hour educational session at the Academy’s 2019 Annual Meeting covering the dermatologic effects of climate change and major weather events, as well as the environmental dangers posed by selected sunscreens. Dr. Coates urged members to single out climate change “whenever the AAD asks about hot topics for meetings, so that our membership can continue to be educated on this really important issue and understand the role of health care providers in addressing it.”
Dr. Boos remarked that “the one thing I hear from my colleagues is, ‘this is important, but I don’t know what to do and I don’t know when I’d have time to do it.’ I would argue that there’s nothing more important than trying to educate, agitate, and advocate for people to just be aware of these issues, and for our government and the hospitals we work for to acknowledge it. If we don’t get everyone engaged about it now, it’s only going to get worse.”
