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When someone has an allergy to hair dye, they are most likely allergic to one of the chemicals in the dye rather than the entire product. The most common cause of these allergic reactions is para-phenylenediamine, also called PPD.
PPD is found in most commercially produced hair dyes. The PPD is usually mixed with peroxide in the dye to alter the hair color. What happens before this reaction is fully complete also makes the PPD more likely to interact with the skin and cause an allergic reaction.
PPD can be found in commercial hair dyes under many alternative names. These include names such as PPDA, 1,4-Benzenediamine, and Phenylenediamine base.
Another common chemical found in hair dye is para-toluenediamine (PTD), which can be tolerated better than PPD but may still cause an allergic reaction in many people.
Allergic contact dermatitis is a reaction caused by the skin being touched by something it is allergic to. Once sensitized, the affected skin will usually become inflamed and red when exposed to the offending allergen.
The scalp, ears, beard, or neck may become red and inflamed. The eyes also may itch, and the eyelids may swell as the reaction develops.
Most contact dermatitis from a hair dye allergy is classified as type 4 hypersensitivity, and it usually takes hours or more for symptoms to occur upon exposure.
Hives may also show up after a hair dye application. The symptoms of these are red, raised, and itchy patches on the body. Someone may experience difficulty swallowing and respiratory problems, such as wheezing and sneezing.
It is also possible, but far less common, for someone to have an immediate, anaphylactic allergic reaction or type 1 hypersensitivity to hair dye, leading up to anaphylactic shock.
Symptoms may include hives, swelling of the face and airways, shortness of breath, and a drop in blood pressure with a fast heart rate and possibly loss of consciousness. Anaphylactic shock can be fatal, and anyone experiencing these symptoms needs immediate medical attention.
One of the difficulties in identifying a reaction to PPD is that symptoms typically will not show up until after the second usage of the product.
The body becomes allergically sensitized to an invading substance the first time it is used. Once it is applied a second time, reactions will often start to appear. Reactions may also get worse with more applications of the product.
It is also possible for people who are not allergic to hair dye to react when using it, leading to non-allergic contact dermatitis or other symptoms.
Some skin types are more sensitive to chemicals, including PPD. This type of reaction may be more common when someone switches brands with different dye formulations.
Most people will find that their skin may become dry, stretched, or cracked. The scalp may tighten or feel as if it is burning.
Symptoms of irritation will usually appear within 48 hours. At the same time, many people with a hair dye intolerance may have an almost immediate reaction to PPD or other hair dye components.
If any symptoms of a hair dye allergy show up, the hair should be washed immediately. The excess dye can be removed through multiple gentle washes with a mild soap and plenty of rinses with clean water.
It may also help to rinse the hair with a solution of 2 percent hydrogen peroxide after washing the excess out. This helps to oxidize the PPD fully and make it non-reactive. This step has mixed results, and it should be avoided if it makes symptoms worse.
Hydrogen peroxide is available for purchase online.
Creams and emollients
Creams with alcohol or certain other chemicals may irritate the skin. Natural creams or simple wet compresses of olive oil and lime may help.
Steroid creams may be used to reduce inflammation with swelling and irritation in cases of stronger allergic reactions.
Some over-the-counter steroid creams may work well enough to manage symptoms if they are less severe. However, more severe allergic reactions may require a prescription steroid cream or possibly oral steroid therapy.
How long do symptoms last?
Symptoms of hypersensitivity to hair dye may last anywhere from a few days to a week or more, depending on the severity of the reaction.
Many alternatives to PPD-containing hair dyes are on the market, though color options may be more limited.
They are PPD-related chemicals, such as hydroxyethyl-p-phenylenediamine sulfate (HPPS), or they do not contain PPD at all, and they work by getting deep into the hair and staining it. Some of these alternative dyes are only available in limited ranges of color, so they may not work for everyone.
Henna is another option for people looking to avoid irritating PPD. True henna is made from crushed plant matter.
Henna usually ranges from an orangish to red-brown color, depending on the other ingredients in it and how it is prepared before it is applied.
Henna is considered to be more allergy-friendly, though there is still the possibility of reacting. A patch test should be used for any henna-containing dye if someone wants to be sure.
It is also crucial to be certain the henna is in fact true henna. Many companies add PPD or its derivatives to their henna-containing hair dyes and market it as henna. These may still cause a PPD-related reaction.
A range of henna hair dyes is available for purchase online.
Semi-permanent and lead-containing dyes
Some people can tolerate semi-permanent hair dyes or lead-based hair dyes, though these options may not be right for everyone. A dermatologist can help determine any chemicals that may be right for every individual they test.
Avoiding a reaction to hair dyes is easy if a few steps are followed. Any or all of these methods can be used to help test for reactions or avoid them
The instructions for each particular dye should be followed closely to help prevent any reactions caused by incorrect usage.
It is important not to leave hair dye in for longer than recommended. While most chemicals in hair dye are considered safe to use, leaving the chemicals on the scalp for too long can be irritating for most people.
Gloves should be worn whenever handling or applying hair dye.
Typically, for permanent dye, the hair and scalp should be washed thoroughly after the application is complete. Poor washing and rinsing leave bits of dye on the hair and scalp. This could cause irritation if the unnecessary dye is left reacting on the scalp longer than necessary. Additional washes and rinses may be required to be certain all the extra dye is washed off the hair and scalp.
Patch tests are done by a doctor and involve putting small, precise amounts of allergen substances in chambers on a small portion of the skin, usually the upper back, to check for allergic reactions.
With oxidizing hair dyes, a person can do an at-home test in a similar way, using the hair dye mixture. One of the simplest places to test is just behind the ear. Following the dye’s instructions on what to do after applying the dye is the best way to ensure a proper test.
Any irritation, reaction, or feeling of being unwell is a sign that the rest of a person’s scalp will have a bad reaction to the product. The product should be avoided in favor of another kind of dye.
If home patch testing or hair dyeing become a regular necessity, many people choose to go to an allergy clinic. Allergy clinics can do their own patch test to help determine what chemicals a person is intolerant of or allergic to. The list of possible irritants can then be checked against the ingredients of hair dyes to find the best one for their use.
Any potentially irritating chemicals should be avoided. A person should be tested to ensure they are not allergic to a chemical or chemicals in hair dye to prevent a reaction. Avoiding further use of the product is key to preventing the recurrence of an allergic reaction.