Understanding reactions, identifying the signs, and keeping everyone in your studio safe — from a pro who has navigated both sides of the chair.

In ten years of working as a full-time lash artist — and applying thousands of sets — I’ve only had two clients develop a genuine allergic reaction. That is a very low percentage, but those two specific cases taught me more about safety than any certification program ever could. Eventually, I even developed a sensitivity myself. Let’s have an honest conversation about what is really happening.

Why do lash extensions trigger allergic reactions?

Currently, there is only one way to perform semi-permanent lash extensions: attaching synthetic fibers to the natural lashes, one by one, with a cyanoacrylate-based adhesive. It is a potent chemical, and, quite frankly, there is no way around it right now.

You have likely heard of "sensitive" or "UV" glues being marketed as safer alternatives. While they are worth investigating, let’s be transparent about how they actually work:

• Sensitive glues contain a lower concentration of cyanoacrylate. This sounds great, but less bonding agent usually equates to weaker retention. If the lashes shed faster, your clients will need fills more frequently, which can actually lead to more adhesive exposure over the long term.

• UV glues are a legitimate innovation and can certainly lower the risk of reactions — but despite what some marketing might claim, they still utilize cyanoacrylate. The primary benefit is a faster cure time, which reduces the window during which fumes are released. However, they are not completely reaction-proof.

• Patch testing is always a good practice to offer, especially for new clients or those who mention previous sensitivities. Just be upfront with your clients: a negative patch test isn't a guarantee of safety. Most reactions build up gradually over months or even years of consistent appointments.

How common are reactions?

Lash allergies are relatively uncommon. More importantly, they almost always develop over time rather than manifesting out of the blue. In a decade of full-time work, I only had two clients become allergic — and both had been coming to me for over two years before they showed any signs of sensitivity. Most seasoned lash artists see roughly one to two reactions every five years.

The Early Warning Sign: If a client mentions that her eyelids have felt itchy or slightly puffy after her sessions, do not brush it off. That is a red flag and the primary indicator that a reaction is forming. Cease treatment immediately. The best pivot is to offer a lash lift instead; these use a completely different chemical process (usually thioglycolate-based rather than cyanoacrylate) and are typically tolerated well by those who have reacted to lash glue.

Both of my clients who reacted were long-term regulars. Once we noticed the symptoms, we stopped the extensions and transitioned them to lifts. Is it a bummer to lose a service? Yes. Is it manageable? Absolutely.

If you're noticing frequent reactions, analyze your technique

If you are dealing with reactions more often than the average tech, it is usually a result of application technique rather than a client's sudden sensitivity. The most common mistakes include:

• Using too much adhesive too close to the eyelid. "Less is more" is the golden rule here. The closer the bond point is to the skin, the higher the risk of a reaction.

• Eyes not being fully closed. If you tape the lashes upward and accidentally expose the waterline, you are drastically increasing contact with fumes through one of the most absorbent membranes on the face.

• The glue drop is too close to the client. Cyanoacrylate fumes aren't just absorbed through the eyes — they are inhaled through the nose and mouth. Keep your glue drop as far from the client’s face as possible. This is a frequently overlooked detail.

Can lash artists develop allergies too?

This is the uncomfortable topic nobody wants to discuss. Clients get occasional exposure, but we are exposed every single working day.

I suffered from migraines for years and blamed them on my long hours. It wasn't until I pivoted away from daily lashing to focus on brand building—even while still working long hours—that the headaches vanished. Every time I assist at a training session now, they return. The connection is undeniable.

Technician reactions often manifest as:

• Persistent headaches or migraines

• Sinus irritation or a runny nose

• Puffy, red, or irritated eyes

• Skin irritation or eczema, especially on the fingertips from direct contact with glue

Once you develop an allergy, it rarely goes away. Prevention is your only defense.

How to safeguard yourself and your clients

1. Ventilate your room properly. If you can, invest in an extractor fan. This is the single most impactful thing you can do for your long-term health as a technician.
2. Wear a face mask and protective glasses. Make it non-negotiable, every single day — not just when you remember.
3. Keep the glue drop far from both faces. Fumes travel further than most people realise, and they're being absorbed the entire time the glue is open.
4. Buy from reputable suppliers. Always check that your lash adhesives comply with local safety regulations. All London Lash glues and liquids are fully compliant.
5. Diversify your treatment menu. Facials, brow treatments, and lash lifts complement extensions beautifully — they allow clients to spend more per visit and reduce your daily adhesive exposure. Your long-term career will genuinely thank you for this one.

A quick word on UV glues

Our UV collection is launching shortly, with the first product arriving in two weeks. To be completely transparent: because UV glues still contain cyanoacrylate, they will not eliminate the risk of reactions entirely. However, the significantly faster cure time means a shorter "fume window," which makes a substantial difference when you consider years of daily exposure.

If you want to be notified as soon as our UV system is live, join our mailing list below.

Wishing you nothing but happy clients and zero reactions.

Hanna Putjato
Passionate lash tech & founder of London Lash

Want to know more about lash safety? [Read more about allergic reactions here].