Safety
hazards with permanent and semi permanent hair dyes
Permanent hair dyes are more sensitizing compared to other types
of hair dye. The chemicals can induce a form of dermatitis (a contact
dermatitis) in people with sensitive skin. Sensitization to a hair
dye does not often occur, but it can and does happen. In most cases
the reaction to the dye is one of itching and some skin redness,
but nothing more. In more severe cases the hair dye may triggers
scaly skin and pain. The distribution of the affected skin can vary
and the affected area does not have to match the exact area to which
the dye was applied. In more severe cases there can be swelling
around the eyes and scaly skin on the ears, face and neck beyond
the actual skin exposed to the hair dye. Sensitization to hair dye
may gradually develop with repeated exposure.
Those most at risk of developing an allergy to the chemicals are
not the people who have the hair dye applied but the professionals
in the hair salon. Their daily exposure to the chemicals on their
skin and in the air they breathe can lead to quite severe sensitization
such that affected salon professionals may have to seek another
form of employment.
Some people are concerned that the hair dyes being used are carcinogenic.
Some of the chemicals involved are carcinogenic, but only at high
concentrations and with prolonged use. For the average individual
with dyed hair the products do not pose a risk. More at risk are
again the salon professionals who are exposed on a daily basis for
many years. Both permanent and semi permanent hair dyes have been
used for some years now, but the long term risks of using these
dyes repeatedly do not seem to be significant for the average user.
Patch
testing hair dyes
In many countries there is legislation that requires hair dye products
to carry a warning about conducting patch testing prior to using
the dye. Patch testing is a wise precaution to make sure that you
are not sensitive to the dye ingredients. Although it is a hassle,
it can save much trouble and pain later on.
The patch test involves applying a small amount of the prepared
dye to an area of skin in an out of the way place. Most frequently,
the skin behind the ear or on the inside of the arm at the elbow
is used as this skin is relatively thin and sensitive. During the
patch test the area of skin used should be left untouched and uncovered
by things like eyeglasses and combs. The duration of test is at
least 24 hours and preferably 48 hours. If redness, burning, itching,
pain, or blisters and eruptions develop at or near the site of application
during the two day test it means you are sensitive to the dye and
you should not use it.
If you have no reaction to the patch test then the dye is safe
to use at that time. However, a negative patch test does not mean
that you will not become sensitive to the dye chemicals later on
so it is a good idea to conduct regular patch testing, even if you
have been using the same product for a long time. With repeated
exposure to a chemical you can become gradually sensitized so while
a patch test may be negative today in a couple of years you may
be sensitized. You must conduct a patch test if you change brands
or if the manufacturers change the ingredients. Treat a "new
improved" formula as a new product and conduct a patch test
with the new formula.
Finally, other damage to the scalp skin can make you more sensitive
than normal to hair dye and other chemicals. If you have any skin
trauma, such as seborrheic dermatitis, you may find you are much
more sensitive to the chemicals.
Patch testing can be done in the one or two weeks before using
the dye. Some salons may want you to come in the day before your
appointment for the patch test, but any time in the two weeks before
is okay. The main principle of the patch test is to define whether
the previous dye application made you sensitive to the chemicals.
So in principle, patch testing any time from a couple of days after
your last dye application up to the day before your new appointment
is okay.
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