The skin around the eyes is by far the most delicate and no matter how cautious we are to eyelash tinting you’ll probably experience one or two clients who will react to tinting in your lifetime as a therapist..

So what can we do as professional therapists to reduce the risk of this from happening?

Eyelash and eyebrow tinting involves the process of mixing up a dye with hydrogen peroxide, however the dye and peroxide that are used are a lot weaker than those that are used in hair dye and hair dye is NEVER used on the eyebrows or eyelashes.
Although most tints are marketed as vegetable dye there is very little evidence that this exists, if a dye is going to deposit colour in the hair, it will definitely contain chemicals. Some tints use synthetic coal tar in their ingredients which is also chemically based, however the main ingredient in most eyelash tint formulas is Phenylendiamine (PPD) and is a chemical that is a popular choice in dyes as the hair can be washed without the worry of the dye running. It is also found in dark coloured cosmetics, temporary tattoos, henna tattoos, printing ink as well as black oil and some gases.
Phenylendiamine requires oxygen to become coloured so hydrogen peroxide is added to the mix and when the two are mixed together PPD starts to oxidise. It is during the oxidisation process that the skin can become particularly reactive, especially if your clients are known to have any allergies or specifically allergies to products containing PABA’s as the risk of them having an allergy to the tint is greatly increased.
Severe reactions can appear as red, swollen and sometimes blistered skin. This is a type of contact dermatitis and can be very uncomfortable for the client. Should the client complain that the skin is feeling irritated, itching or there is a burning sensation during the tinting process, then you must remove the tint IMMEDIATELY and flush the eyes out with plenty of cold or tepid water to neutrilise the tint.  However some clients don’t react for a few hours after the treatment and it is very difficult to know what to do once they have left the salon.
Hydrogen Peroxide:
Hydrogen peroxide is a weak acid, and oxidising agent and is the other ingredient used in tinting the eyelashes or brows. When mixed with the tint it allows the oxygen to be released from the dye, this process is called OXIDISATION. Hydrogen peroxide is slightly thicker than water and in it’s purest form can be used as rocket fuel, luckily for us most household hydrogen peroxide solutions are diluted to between 2 – 5%.
Lash tinting it is 2 – 3%,
Topical Acne products are usually 1 – 3%
Teeth whitening about 6%.
Hair dyes about 12%
It is also used as bleaching agent for paper, and some foods – in particular mushrooms, however hydrogen peroxide breaks down naturally in the soil so there is no adverse effect on the food chain, now you know why they look so white at the supermarket. There are no known disease causing bacteria or fungi that can survive when they are exposed to hydrogen peroxide so it is very often used as a steriliser to wipe down surfaces in hospitals and vet clinics.
Concentrated hydrogen peroxide (anything above 15%) can be toxic if it is ingested or applied topically and workers who are exposed to this level need to wear protective clothing, eye wear and mouth covers.
Adverse effects of hydrogen peroxide to tinting treatments:
Eye exposure to 3% hydrogen peroxide may result in redness and stinging, but severe injury is rare.
More concentrated solution (5% and above) may result in ulceration or perforation of the cornea. Permanent eye injury, including blindness.
Skin contact can cause irritation and temporary bleaching of the skin and hair.
Contact with concentrated solutions may cause severe skin burns with blisters and ulcers.
If your client experiences any feelings of irritation, stinging, or burning during the tint then remove it IMMEDIATELY and flush the eye thoroughly with cold water.
To patch test or not to test?
When training to become a therapist you are taught that you must always patch test at least 48hrs BEFORE the tinting procedure, especially if it is their first time. The best place to patch test is behind the ear as the skin is closest to the eyes. Even with a negative patch test result the client can still react during or even after the treatment.
A NEGATIVE patch test means that there has been NO reaction to the tint and it is safe to proceed with the treatment.
A POSITIVE patch test means that the skin will usually look irritated, red or even blistered. A reaction like this indicates that it is NOT safe to proceed with the treatment and you must advise the client accordingly.
Although it is advisable to patch test clients every time we can get lazy with our regular tinting clients as we assume that nothing will go wrong because nothing has so far. My advice would be to regularly patch test as the skin’s acidity can change over time and also with the seasons. It is especially important to patch test if your client is on medication or has a history of allergic reactions, as these factors can contribute to more hyper reactive skin.
Medication such as sulphonamides (antibiotics), or local anethetics containing benzocaine or procaine can also contribute towards an allergic reaction to occur when PPD is present. Check with your clients if they have recently changed their skin care products. If they have used or are using products containing PABA (sunscreen) and have become allergic to this ingredient then it is highly likely that they will be allergic to the tint.
If your client reacts to the tint then they are experiencing a histamine reaction. Histamine is a chemical produced in the immune system by the body and is neurotransmitter that communicates with the nervous system and brain to let you know what’s going on and which allergens to attack. Histamine causes the blood vessels to swell, or dilate, so that the white blood cells can quickly find and attack the infection or problem, it is natural response of the immune system. Histamine’s role in the body is to cause an immediate inflammatory response. It serves as a red flag in the immune system, notifying the body of any potential attackers and this is exactly what happens during a wax treatment, hence the plucked chicken look or during or after an eyelash tint.
A reaction to an eyelash tint is caused by the body releasing histamine in reaction to a particular chemical. The client may complain of intense itching, a sensation of burning, or a grittiness in the eyes, redness and swelling. It can usually be suppressed by taking an anti-histamine and immediate removal of the product. If there is no ease from the reaction I strongly advise that immediate medical attention be sort.
Steps for successful tinting
• Ensure that you apply a barrier cream around the eyes to prevent the tint from leaking into the skin; Vaseline is suitable although some people are also allergic to this too, so you’ll need to find an alternative.
• Apply the Vaseline as close to the lash line as possible without it touching the lashes.
• Place a dampened cotton pad or tissue under the eye.
• Make sure that the tint that you mix is not too runny. Ideally you should use the 2:3 ratio when mixing up tint.
• Ask your clients to close their eyes whilst you apply the tint
• Apply the tint without getting it on the skin. If this does happen then wipe the excess tint off immediately with a damp cotton bud.
• Cover the eyes with cold damp cotton pads during the oxidisation process. I have heard of some schools teaching the tinting procedure with the eyes uncovered as it helps the tint to oxidise quicker reducing treatment time. Personally (and through experience) I prefer covering the eyes because this will ensure that the client keeps their eyes shut during the tint phase and also the coolness of the cotton pad will help to keep the eye area cool and soothed.
• When removing the eyelash tint make sure you use damp cotton pads and damp cotton buds to remove as much of the tint as possible. Always wipe downwards and away from the eye area just to be extra cautious.
• As a precaution, flush the eyes out afterwards, especially if your clients have complained of a ‘stingly’ sensation either during or after the tinting procedure.
• Always give your clients aftercare advice. This should include simple things such as ‘no rubbing’ the eye area, and avoid putting on make up for a couple of hours afterwards or even sunscreen around the eyes.
• Remember that the tint will carry on oxidising for at least 2-3hrs after you have removed it so a reaction is even possible once they have left the salon
• Never leave your client whilst the tint is on. You can always perform a lovely relaxing head or hand massage to make your clients feel extra pampered.
• And remember to always check for contraindications.
As long as you follow the protocol, carry out a patch test, check for contraindications and give the correct after care advice then you really have nothing to fear. At the end of the day you have done what you have been trained to as a professional beauty therapist, whether or not the client chooses to listen to your aftercare is up to them and what they do when they leave the salon is not your responsibility.  If a client has reacted previously to a tinting treatment, I would be less inclined to carry out any future tinting services on them again as this can sensitise the skin further.  However if the client insists on a tinting treatment then they do so at their own risk.
It is not unusual for that one client who has always had tinting to suddenly react one day no matter how meticulous and cautious you are. It is possible that they have developed an intolerance to tinting over time or they've changed their medication or it is possible that they have changed their skin care products and not thought to mention anything to you because they’ve always had tinting done and have never reacted in the past, but as a therapist it is always worth asking before you proceed with the treatment, and remember to write everything down on the consultation card. 
As with any treatments regarding the eye area, tinting the eyelashes or eyebrows carries a risk and the client needs to understand that by participating in this service then they do so at their own risk.