An “exotherm” is a scientific term that means “to release heat”. This is what occurs when nail coating products get hot during application. It is commonly known as heat spikes. Both UV gels and L&P systems can become warm, even hot during application. Becoming warm isn’t a problem, and is considered normal for products that cure or polymerize to create a nail coating. But when the coating overheats, this can be painful for clients. Even so, nail coating exotherm (EK-so therm) can cause other problems besides burning pain. This type of overheating can lead to nail bed damage and infections. It is important to understand why these issues occur so that you can avoid them. Let’s look at the most common reason clients feel excessive heat when these types of products cure.
UV gels and monomer liquids are both made using acrylic ingredients and chemistry, and there are NO exceptions to this rule. Curing occurs as millions of tiny, invisible molecules begin to permanently join together to create many growing polymer chains. Each time two molecules react to join together, there is a release of a very tiny amount of heat. The heat released by one molecule joining a chain is FAR too small to detect. However, when a coating cures on a single nail plate, it contains many millions of molecules. Many millions of molecules joining together release millions of times more heat. Of course, this normally occurs on every nail plate, and usually doesn’t create any problems. However, excess heating can become painful and potentially damaging under some circumstances. This can occur with all types of artificial nail coatings and adhesives.
When nail coatings are properly formulated, properly applied, and properly cured, the small amount of heat that is released usually goes unnoticed. Some products are not properly formulated, and may have a tendency to overheat, even when properly applied. This is unusual because reputable manufacturers run quality control tests to ensure the heating is controlled so that it won’t become excessive. This is one of many reasons for only purchasing such products from reputable manufacturers. Nail product developers pay very close attention to this issue, and design their products to slowly release heat during curing, rather than to suddenly release it as heat spikes.
Even normal levels of heat become much more noticeable if the nail bed is injured, e.g. from aggressive over filing. Why? The nail plate insulates the nail bed from heat but, if the nail plate is overly thinned by filing, it becomes a poor heat barrier. This allows heat to flow through the plate into the nail bed, in some cases to cause injury. Also, overly aggressive filing techniques can “friction burn” the nail bed, making it super-sensitive to even small amounts of heat that would normally go unnoticed. For example, if I rub my arm with my fingers five times, that doesn’t harm it but, if I do that 500 times, I’m likely to damage the surface of the skin. Or if I push down harder and rub 50 times, I can still friction burn my skin. The same is true when filing the nail plate.
Do not burn the nail bed! File gently and avoid coarse abrasives that thin the nail plate. The nail bed doesn’t contain any heat detectors but does contain pressure detectors. You can feel these detectors activate if you pressed down hard on the nail plate. That’s why you can feel applied pressure to the nail bed. However, when the nail bed gets hot enough, this will trigger the pressure detectors to create painful burning sensations. Generally, these detectors won’t be triggered until the temperature of the nail bed exceeds 115oF or 46oC. When that occurs, the nerve endings under the nail plate can go off like a fire alarm in the brain. The brain sends a pain strong signal back to the nail bed to warn it of potential danger. Friction burns can damage the nail bed, make it very sensitive, and cause it to overreact to even warm temperatures.
What can cause a l&p formula to overheat? Using the wrong polymer powder with the monomer liquid can definitely cause these types of nail coating products to overheat. That is why it is important to only use polymer powders designed for the monomer liquid of your choice. “Fast setting” nail coatings actually release the same amount of heat as those with a traditional set time, however, they do so in a shorter time period. This heat may go unnoticed when released over two or three minutes, but this same amount of heat becomes very noticeable when released in one minute or less. This is especially true if the nail bed has been friction burned by overly aggressive filing techniques. Fast-setting nail coating products aren’t for everyone. They are best used in cold climates. That’s because the room temperature plays a big role in determining how quickly these l&p nail coatings will harden (polymerize). Fast set nail coatings are much more likely to overheat when used on warm days.
UV cured gel nail coatings can also create heat spikes, especially on friction-burned nail beds. Heat spikes that occur during the cure of UV gels can be caused by using the incorrect UV nail lamp. For example, a UV gel nail coating designed to cure with traditional, fluorescent style UV nail lamps will likely overheat when cured with a LED-style UV lamp. LED-style UV nail lamps produce more UV than traditional style nail lamps. That’s why they cure nail coatings more quickly.
When a UV gel nail coating designed to cure in 2 minutes under a fluorescent-style UV nail lamp is cured in 30 seconds with a LED-style UV nail lamp, all of the heat is released in one quarter of the time. This is what can create painful burning sensations, and that may result in onycholysis (on-EE-ko-LY-sis), or separation of the nail plate from the nail bed. Onycholysis can lead to nail bed infections. Of course, there are other reasons for onycholysis. No matter which type of nail coating you use, the more thickly the nail coating product is applied, the more heat will be released. That’s often why larger thumb plates feel warmer, compared to smaller nail plates.
To avoid these problems here are some general rules to follow:
- Avoid friction burns of the nail bed – Don’t Burn the Bed!
- Don’t overthin the nail plate, keep it healthy and intact.
- Use the correct polymer powder with monomer liquid of your choice.
- Avoid using fast setting L&P nail coatings when working in warm salons.
- Use the UV nail lamp recommend for use by the UV gel manufacturer.
- Avoid applying product too thickly, especially UV curing gels.