HEMA allergy: why gel nails cause it and regular lacquer does not

In 2018 the British Association of Dermatologists warned of an allergy epidemic caused by artificial nails. Since then gel polish has moved from the salon to the kitchen table, and dermatology clinics in the UK, Spain and Israel have described the same pattern: young women, itchy fingertips, loosening nails, and a positive patch test to a molecule called HEMA.

What HEMA is, why gel causes the allergy and regular lacquer does not, what the symptoms look like, and what the EU professional-only rule means for a bottle bought online, with the regulation text and the dermatology sources behind each point.

What is HEMA and what does it do in gel polish?

Hydroxyethyl methacrylate (HEMA) is a methacrylate monomer that helps gel polish stick to the nail plate and flow into a smooth coat. It is a small molecule, which is what makes it useful and what makes it a risk: small molecules penetrate skin. In professional gel systems HEMA concentrations typically run from 4 to 35 percent, with 35 percent treated as a ceiling⁴.

Gel polish hardens by photopolymerisation. A photoinitiator absorbs light from a lamp at 365 to 405 nanometres and starts a chain reaction that links the monomers and oligomers into a hard cross-linked film⁸. The problem is the gel that never cures: the smear on the cuticle, the flooded sidewall, the thick coat the lamp could not reach through.

Why does gel polish cause acrylate allergy?

Uncured monomer on the skin is the cause. Methacrylates are contact sensitisers: with repeated skin contact the immune system learns to recognise them, and from then on every contact, even a small one, produces an allergic reaction. The EU's Scientific Committee on Consumer Safety concluded that HEMA and its relative di-HEMA trimethylhexyl dicarbamate are weak to moderate sensitisers that pose a risk of sensitisation². Weak means more contacts are needed before the allergy sets in, not that it is rare.

The 2017 audit that prompted the British warning covered 13 UK dermatology units and 4,931 patients. Of those tested, 2.4 percent were allergic to at least one methacrylate and 1.5 percent to HEMA; 93 percent of those affected were women, and 60 percent had become sensitised through their own nail enhancements or glue, with a further 33 percent through work as nail technicians¹.

Once acquired, the allergy reaches beyond nails. The same methacrylates are used in white dental fillings, orthopaedic bone cement, glucose sensors and insulin pumps, so a person sensitised by gel polish can react to future medical and dental treatment³.

Why is the allergy rising with home gel kits?

Three things go wrong at home more often than in a salon. The lamp may be the wrong one: gels are formulated for a particular wavelength and power, and a lamp that does not match the gel leaves the underside of the coat soft. The coat may be too thick for light to reach the bottom. And the gel touches skin, because a beginner floods the cuticle and sidewalls and cures over it. Each puts uncured monomer on the skin for hours.

The British Association of Dermatologists repeated its warning in 2023 with a focus on at-home kits, noting that salon closures during the pandemic pushed more people to home use and that home kits pose a great risk to the user because of inexperience with the products. In the same year the UK Office for Product Safety and Standards opened an investigation into gel nail products causing allergies and asked the public to report reactions to trading standards³.

Spanish dermatologists have described HEMA sensitisation as a global epidemic at its peak in their country, and their earlier work traced many cases to long-lasting nail polish kits for home use⁶. Salon technicians protect themselves with nitrile gloves changed every 30 minutes and a no-touch technique.

What are the symptoms of a HEMA allergy?

The first signs appear on and around the nails. The skin at the fingertips becomes red, itchy and sometimes blistered. The nail plate can loosen from the bed and in severe cases come away. Because hands touch the face, eczema also appears on the eyelids, cheeks and neck. Rarely, breathing problems occur¹.

The reaction is confirmed by patch testing, in which small amounts of the suspected chemicals are taped to the back for two days. Since the 2017 audit, British dermatologists have been advised to patch test to methacrylates routinely¹. See a GP or dermatologist for any rash that follows a gel set, and stop using gel until the cause is known.

What does the EU professional-only rule say?

Commission Regulation (EU) 2020/1682 added HEMA and di-HEMA trimethylhexyl dicarbamate to Annex III of the Cosmetics Regulation as entries 313 and 314. Both may be used in nail products for professional use only, and the label must state the words for professional use only and the warning can cause an allergic reaction. Non-compliant products could not be placed on the EU market from 3 June 2021 and could not be sold through from 3 September 2021².

The effect is that a gel polish sold to a consumer in the EU must be free of HEMA, and a bottle that contains it should say so and be sold only to trained professionals. Practice lags behind the law: a 2024 online market survey published in Contact Dermatitis found widespread non-compliance among gel products sold to consumers online⁵. A consumer gel with HEMA in its list, or with no ingredient list at all, is one to leave in the basket.

Consumer brands have responded with HEMA-free formulas; the Dutch gel brand LAKKIE, for example, labels its cat-eye gel as HEMA and TPO free⁹. HEMA-free removes the most common sensitiser, but other methacrylates can still sensitise, so skin contact and full curing matter as much.

Why is regular nail lacquer different?

Regular lacquer is a film of nitrocellulose, resins and plasticisers dissolved in solvents. It dries by evaporation: the solvents leave, and the nitrocellulose film that remains is a finished polymer, made long before it went into the bottle⁷. There is no monomer to cure and nothing for a lamp to do.

Lacquer can cause allergy too, through a different route. The adhesion resin tosylamide/formaldehyde resin is a known contact allergen, which is why it appears on 5-free lists¹⁰. A person with a methacrylate allergy can usually wear a resin-free lacquer without trouble, though a dermatologist should confirm which ingredients to avoid. The India Anaïs lacquers are air-dry lacquers of this type; the first edition is sold out and the next edition is planned for spring 2027.

How to lower the risk if you still want gel

You will need: a HEMA-free gel from a brand that publishes a full ingredient list, the lamp that brand specifies for that gel, a fine brush for clean-up, nitrile gloves if you paint someone else's nails, and the patience to keep gel off skin.

1. Choose a professional application where you can; a trained technician works no-touch with a matched lamp.
2. At home, use only the lamp made for the gel. Wavelength and power decide whether the coat cures through.
3. Paint thin coats and stop a hair's breadth short of the cuticle and sidewalls. Any gel on skin is uncured gel on skin.
4. Wipe away any smear before curing, with a clean brush, and cure for the full time stated.
5. Soak off a lifting edge; picking exposes half-cured gel.
6. Stop at the first itch, and see a dermatologist. A reaction that is ignored becomes a lifelong allergy.

“We would particularly urge people to be careful when using home kits.”

Dr Deirdre Buckley, Consultant dermatologist, Royal United Hospital Bath, and President of the British Society of Cutaneous Allergy, quoted by the British Association of Dermatologists

Written and fact-checked by the India Anaïs editorial team. Every number and rule is linked to its source. How the guides are made.