Facts about hair dye allergy facts

Ageing causes a reduction in the melanin pigment in the hair, resulting in the hair losing its youthful colour and greying. Hair dyes are used routinely to cover grey hair and restore the buoyant colour that once existed.

Permanent hair dyes are also used to change the colours of one's hair to a different shade for added appeal and for enhancement of one's looks.

Hair dyes, unfortunately, result in allergic reactions in about 5% of the population. Hair dye allergy is characterized by a condition called contact dermatitis. Hair dyes are the third most important cause of allergic reaction due to chemical preparations, rating below perfumes or sprays and preservatives.

The risk factors for people to acquire such an allergy depends mainly on the genetic make up and heredity factors. Certain people are more susceptible to allergic reactions due to such chemicals because of their genetic predisposition.

The most common symptoms that are seen as a result of hair dye allergy are redness and itching of scalp. This could also be associated with swelling, pain and scaly skin on the scalp that resembles dandruff. Some hair dye users even complain of nausea on application of the hair dye, swelling around the eyes and scaly skin surrounding eyes, neck and over the face. In extreme cases of hair dye allergy, the allergic reaction towards hair dye could lead to anaphylactic shock. This is characterised by fall in blood pressure, swelling of the face, difficulty in breathing and if no immediate help is available, death.

The allergies to hair dye are caused due to the presence of 4-ParaPhenylenediamnine in the hair dye. Hair dye is applied to the hair after mixing PPD based dye, which is non -oxidised and therefore colourless, and hydrogen peroxide or any other oxidising agent. The peroxide breaks down the melanin pigment present in hair and this is replaced by PPD. When PPD is oxidised while reacting with the peroxide it becomes coloured, this process causes the allergic reaction in susceptible people. When such people are protected with fur coats, they do not come in contact with PPD during the process of oxidisation and thus the symptoms of allergy are not expressed. Fully oxidised PPD does not cause any allergic reaction.

Apart from PPD, there are other related chemicals present in hair dyes that can cause an allergic reaction in people like p-methyaminophenol, isatin etc.

Since PPD is such a strong allergen for many people, other chemicals that are used in hair dyes include

• P-aminodiphenylamine(PADA)
• paratoluene diamine(PTDA)
• 3-nitro-p-hydroxydiaminophenol

These chemicals cause fewer reactions when compared with PPD but people already sensitized to PPD will still be affected by these chemicals.

These allergic reactions are caused even when the dye is used for the beard resulting in beard dye allergies. Any part of the skin which is subjected to contact with such dyes will react adversely for those susceptible to this form of allergic reaction. Hairdressers who have been found to be allergic to such dyes develop rashes in their fingers due to contact with these dyes.

The treatment for hair dye allergy includes the following:

1. The hair should be completely washed with shampoo to remove as much of hair dye as possible
2. As oxidised PPD does not cause the allergic reaction, hydrogen peroxide may be added to completely oxidise the PPD
3. Corticosteroid creams may be applied on the rashes to reduce their intensity
4. The blisters that are present on the scalp may be slowly removed by application of olive oil and lime. These will help in making the crusts of the blisters soft and facilitate healing.
5. Over the counter skin creams will help reduce itching associated with the rashes.

In order to safeguard oneself from such allergic reactions, a patch test should be performed before a particular hair dye is used. A patch test involves application of the hair dye to the skin behind the ear or on one's arm on the inner elbow to reveal any sensitivity. The instructions that are provided along with the hair dye should be followed while trying the patch test. A period of 24-48 hours should be allowed after the patch test to check for any adverse reaction. The indications for allergy will range from mild rashes to blisters.

When a permanent dye has been tried and if it resulted in an allergic reaction, then a non-permanent dye may be opted for. Before resorting to a non-permanent dye, ensure that blisters and rashes that were caused as a result of application of the permanent dye used previously have completely healed. Otherwise, chemicals present in the non-permanent dye could aggravate the situation further.

The content and the label of hair dyes should be read carefully before purchase. Many dyes that claim to be natural may have a mix of azo dyes that have also been found to result in an adverse reaction in certain people.

Henna is one of the best natural dyes and it can be used to colour one's hair. However, even pure henna has been found to cause an allergic reaction in people, though the numbers are very few. Other than henna, metal pigment dyes are other options that are available for usage.

The only sure way to avoid hair allergy due to the usage of hair dyes is to completely avoid dying one's hair. There are many who do not dye their hair and look great, including popular celebrities. Wear the right attitude and it won't matter what colour your hair is.

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