Lots of lip service is paid to how light (whether it’s UV from the sun, blue light from our computers, or LED treatments) affects our skin. But what about heat? The two go hand in hand, particularly in the warmer months when an ideal long weekend looks like a cool drink, a good book, and a war of attrition between you and the afternoon sun. And it turns out that if you’re irritated by overheating, your skin probably is too.
A heat reaction can look like lots of different things, but at the root of them all is inflammation. Here's what you should look for:
“Sensitive skin conditions such as eczema and rosacea can sometimes flare during the summer months,” says board-certified dermatologist Dr. Stacy Chimento, who’s based in Miami and used to doling out advice for overheated skin. “Excessive heat can also exacerbate acne and folliculitis,” she adds, pointing to a familiar chain of events: heat leads to sweating, which provides bacteria with an ideal breeding ground full of nutrients. Beyond those common reactions, you might get a rash—heat rash is clusters of clear fluid-filled or red blisters, and on the more extreme end, Dr. Chimento notes that some people develop a rash of itchy red bumps on their chest and back known as Grovers. (It’s more common in men.) Finally, those who wear heating pads or work with their laptops in lap may be more susceptible to a condition called erythema ab igne, a net-like rash.
Splotches Of Excess Melanin
As the Skin of Color Society notes melasma predominantly affects people of color, a point which dermatologist and founder of @brownskinderm Dr. Adeline Kikam emphasizes. “Heat-induced inflammation stimulates melanin formation,” explains Dr. Kikam, “and because people of color produce more melanin than those with pale skin they tend to be more prone to hyperpigmentation.” Of course, it's just more common for melasma to be triggered by infrared heat—that doesn't mean it can't flare from other sources of heat, too. "In fact, studies have shown that chefs who are by the oven all night and do not go out during the day suffer from significant facial pigmentation," says Dr. Joshua Zeichner, Director of Cosmetic and Clinical Research in Dermatology at Mount Sinai.
A "Permanent Bruise"
Dr. Kikam also mentions another type of hyperpigmentation called hemosiderin staining, sometimes referred to as permanent bruising. “It's theorized that continued exposure to heat damages superficial blood vessels, which causes red blood cells to break down,” says Dr. Kikam. These blood cells leave behind hemosiderin, which appears as dark patches on the skin. And researchers note that hemosiderin staining is usually more prominent on areas frequently exposed to sunlight.
Unlike sunlight, it’s essentially impossible to avoid heat altogether. It’s everywhere, and you can't exactly tape ice packs to your skin and call it a day. However, there are some practical, real-world ways to minimize the heat you encounter on a daily basis. First off, the obvious: avoid unnecessary overexposure by elevating your laptop, limiting your time in the hot sun, and sitting a good distance from any, er, bonfires you may be attending. Traditionally “good” sources of heat, like facial steam and infrared saunas, can still trigger the above skin conditions, so if you know you’re prone to rosacea, eczema, or hyperpigmentation you should try and avoid those all year round. (Many aestheticians give steam-free facials for this very reason.) You can combat some side effects of heat exposure, primarily rashes, by sticking to loose-fitting clothing—Dr. Chimento notes that gym clothes and leggings are “famous culprits” because all that close contact irritates the skin and can block sweat ducts.
Choose an appropriately lightweight facial protective mask for summertime, and store them in the fridge to keep cool when you head out. In addition to physical irritation, masks also trap body heat close to the skin. For the same reason, heavy occlusive creams should be avoided—Dr. Chimento says that, specifically, moisture-locking petrolatum can exacerbate rashy skin conditions.
Beyond that, you should protect your skin from heat the same way you do from UVA and UVB rays—infrared light, which is a form of heat, comes from the sun. “Using topical antioxidants in skin care can theoretically be helpful in countering free radical damage done by infrared light,” says Dr. Kikam, though she adds that this warrants further studies. Regular ol’ broad spectrum sunscreen can also help mitigate your overall risk. And while researchers once thought that it was best to avoid chemical sunscreens (which absorb harmful rays and turn them into heat) in favor of mineral ones, we now know that's only partly true. Dr. Zeichner explains, "Mineral sunscreens like zinc oxide do reflect and scatter light but they also absorb UV rays similar to chemical blockers." However, the nitty gritty research still needs to be done—as Dr. Kikam notes, the jury's still out on which type of sunscreen releases the most heat.
If you have darker skin prone to hyperpigmentation, or sensitive skin prone to reactivity, you’re still probably better off choosing an inorganic, mineral-based sunscreen just to be safe. “Inorganic sunscreens provide better broad spectrum coverage, are less likely to break down upon exposure to sunlight compared to some chemical filters, and are less likely to provoke irritation,” says Dr. Kikam. And if you're particularly concerned with melasma, Dr. Zeichner recommends a mineral, tinted sunscreen. "Tinted sunscreens use pigment from iron oxide," he says, "which helps protect the skin against damage from visible light." Luckily, when it comes to sunscreen, you have lots of options.
Photos via ITG