Symptoms and Specifics: What's the Difference Between Chemical Burns and Allergic Reactions, and What Can You Do About Them?

Do eyelash extensions cause damage? As long as you apply them correctly, no, they don't. Two things that can lead to client discomfort even if you have applied the lashes perfectly though, are chemical burns and allergic reactions.

What is the difference between allergic reactions and chemical burns, and what can you do to prevent them?

What's the Difference Between an Allergic Reaction and A Chemical Burn?

To put it simply, chemical burns are inside the eye. You’ll notice redness in the eyes and they will be bloodshot. These occur during treatment and will go down on their own after a few days. Chemical burns can happen in one or both of the eyes.

Allergic Reactions affect the outside of the eyes. They will cause the eyelids to swell up and become uncomfortable, and sometimes the eyelids will be hot to the touch. It's more common for an allergic reaction to occur in both eyes at the same time, but it can happen in one eye only.

What Doesn't Cause Allergic Reactions to Lash Extension Glue?

First things first, let's talk a little bit about what our clients are actually allergic to when they have an allergic reaction after getting a set of eyelash extensions. contrary to surprisingly common belief, it's not the lashes themselves.

This is hardly a mind blowing thing to say; it’s been years now that eyelash extensions have been made from a hypoallergenic fiber called PBT, and not—as the names may suggest—Silk, Mink, or Cashmere.

different types of eyelash extensions

We went into a bit more detail about the different types of eyelash extensions in another blog post, but to keep a long story short, these names simply let you know that there is a difference in appearance between the different types of lashes.

So What Does Cause Allergic Reactions to Lash Extension Glue?

The most common culprit of allergic reactions and chemical burns is your glue. And no, a client having an allergic reaction or getting chemical burns is not a reflection on the quality of the glue.

More specifically, both of these issues are caused by cyanoacrylate fumes. You’ll know as well as anyone that cyanoacrylate is the main ingredient in any lash glue; it’s what makes the glue stick. It also happens to be a pretty strong chemical, so can cause irritation in some circumstances. 

Who Can Get Chemical Burns?

In short, anyone. A chemical burn is a direct result of the eyes being open during treatment. 

There are a few different reasons that a client can get chemical burns, and generally speaking they are preventable. Chemical burns happen if:

  • Your client gets up to check their phone part way through treatment,
  • Your client's eyelids are flickering because they’ve had caffeine or sugar prior to treatment, or if they've done an intense workout (endorphins!),
  • Your client's eyelids are flickering because they’re chatty during treatment,
  • You were resting on the eyepatch with your isolation tweezers too hard and pushing the lower eyelid down (it’s easily done),
  • Your client has bulbous eyes that won’t completely close
red eyes after lash extensions

How Can You Prevent Them?

  • Advise that they avoid caffeine and sugar for at least an hour prior to treatment, and to book their lash appointments two hours of more after intense workouts
  • Weigh down the top eyelid with foam tape or a sanitized coin to prevent it from moving too much and opening up during treatment
  • Take a strip of eyelid tape and use it to hold the eyelid closed while you work
  • Play relaxing spa music while you work to help them fall asleep, or invite clients to listen to music in their earphones
  • Use foam tape instead of under eye patches to hold down the bottom lashes, preventing the fumes getting into open eyes
  • Double check the placement of eyepatches. Eyepatches or tape being placed too close to the waterline will be uncomfortable for your clients and will cause their eyes to move more
  • Check throughout treatment with a Lash Mirror to ensure the eyes are fully closed during treatment
  • Lighten the pressure on your isolation tweezers. It takes a little bit of practice to not push down on the eyepatches while you isolate, but you'll get there! Just be mindful of it, and let your tweezers hover, or just rest on the under eye patches 
  • Have clients silence all alarms and their phone while they're having their lashes done. This is supposed to be a relaxing time, after all! 
  • Lastly, try finishing your set with Superbonder to lock in glue fumes by instantly curing glue while keeping it flexible.
lashes being checked from underneath using a lash mirror

What Can We Do if A Client Has A Chemical Burn?

There's not much we can do if a client already has red eyes after eyelash extensions, which is why it's better to prevent them.

The redness will go down within a few days and, while it's not completely free from discomfort, it often looks worse than it actually feels.

Eyes will feel sore and dry, so directing your client to a pharmacist is a good idea to see if they are able to get anything to help alleviate their discomfort. Remember that as we are not medical professionals, we should never recommend any medicine for our client, even something as simple as eye drops!

Can Someone Have Lashes Again After A Chemical Burn?

Yes, you'll just need to make sure their eyes are completely closed during the treatment, and cure the glue at the end.

Something else to consider is investing in a Glamcor Flow which will help to blow away glue fumes while you work, helping with chemical burns to a degree, but also doing you a big favor where breathing in glue fumes is concerned.

Also be sure to explain to clients who like to visit saunas and steam rooms that they may sometimes experience burning and potentially redness, as the extreme heats can cause their lash extension glue to soften.

Who Can Have Allergic Reactions?

Again, everyone. Allergic reactions are less common than chemical burns because they're not caused by client or Lash Technician behavior. It’s actually more likely that your client of 5 years who has never reacted will send you this text than the person who came to you for the first time last week who’d never had lashes before.

This is because an allergy to chemicals is accumulative, it is the result of the body building up a reaction over time and eventually telling you ‘I don’t like this!’

This is why if we’re doing bridal lashes for ANYONE, we have a trial set one month prior to the wedding, and apply the full set one week before, just in case of a reaction. 

swollen eyelids due to an allergic reaction to eyelash extension glue

That’s not to say everyone will have a reaction eventually or that new clients won’t, some clients just do. It is simply a developed allergy that can happen at any point.

Our cells regenerate and our body changes as we grow and experience different environmental factors, so it’s not unusual for our bodies’ responses to stimuli to change. 

What Can Be Done to Minimize The Risk of Reactions?

Well, not much to be honest. If a client is allergic, they will have an allergic reaction.

Sometimes the advice is for the client to take a break from lashes, for you to use a slower drying glue (slower drying = less cyanoacrylate), or to use faster drying glue (faster glue equals more cyanoacrylate, yes, but faster curing = less exposure time) or to use Superbonder (which cures the glue instantly after treatment, so again, less exposure to fumes), but clients may still react.

It is very hard to predict when or even if someone will react, but the fact is that once a client has had an allergic reaction to lash extension glue, you shouldn't do their lashes again, as subsequent reactions are likely to become worse due to them being accumulative.

What About Patch Tests?

Patch tests are never 100% accurate. When you carry out your patch test, you are applying a few extensions per eye but you are using far less glue in this case than you would be in a full set.

You cover 10-20 lashes during a patch test, compared to 80-150 during a full set, which is a huge difference in the exposure to glue fumes.

Plus, this type of allergic reaction being a developed allergy means that they may be perfectly fine after a patch test and a few appointments, but then suddenly and unpredictably react one day.

classic eyelash extension application

What Can We Do if A Client Has an Allergic Reaction?

First and foremost, get your client to send you a photo of their eyes. The reason for this is that it might not actually be an allergic reaction (ie. they've got a chemical burn), and because it means that you can actually see what you might be up against. 

Remember, we can't advise them on medical steps to take, but we can advise them to visit a doctor or a pharmacy to see if there is anything to reduce the reaction symptoms.

It's good practice to remove their lashes, as sometimes the swelling can press on the glue bonds which increases their discomfort, but once the glue has cured completely the reaction won't continue so it's not the worst thing to leave the extensions on if you need to wait a few days for the swelling to go down, before you can remove.

If Someone Had an Allergic Reaction, Can They Have Lashes Again?

It’s best not to. We’ve gone over this kind of reaction being accumulative, which means that each subsequent reaction is likely to be worse than the last. If the body becomes more and more allergic to something, it can go into anaphylaxis as a result. 

Consider too that the majority of insurance providers will not cover you in this situation, as you will be performing a treatment while being aware that your client has a clear contraindication to having eyelash extensions. Basically, you're putting them at risk by performing the treatment.


While allergic reactions to lash extension glue aren't common, they are a genuine fear of Lash Technicians, and something that clients should be forewarned about. While there is no foolproof method of preventing them like there is with chemical burns, knowing what to look out for and how to advise clients takes at least some of the worry out of that eventuality.