These are mixtures of para (paraphenyle-ondiamine or paratoluendiamine), and some other chemicals (such as pyrogallol and resarcin). Hydrogen peroxide is also used in dyes to accelerate the oxidization of the hair. Chemical dye forms a kind of lacquer which settles on the cuticle or outer part of the hair and penetrates it. This lacquer does not reach the hair root. Chemical hair dyes .overcome all the disadvantages of the vegetable dyes, such as they require short exposure time on the hair, provide natural color, are obtainable in many shades, and are water-proof or shampoo-proof. However, the biggest dis3.dvantage of the chemical dyes is that they may have an adverse effect on some skins. The symptoms of such ill-effects are violent itching all over the scalp which starts soon after the dyeing or any time within 48 hours after dyeing. This is quickly followed by swelling of the scalp, the ears, the eyelids and also the face. Should such a misfortune happen to you, do not be too upset. The swelling will go down rapidly and the eczema is cured quite quickly if the correct treatment is given. You should immediately consult a dermatologist.If the services of a specialist are not immediately available, here are two simple home remedies to avoid further mishaps. Rinse the hair with a solution of sodium chloride(kitchen salt) diluted in water. Mix 100 gms salt to one liter of water, to which add a tablespoonful of hydrogen peroxide (20 vol). Rinse twice daily. Another remedy is to apply to the swollen part, for fifteen minutes after every three hours, a clean handkerchief soaked in the solution of camomile flowers. The preparation is made by putting camomile flowers in a cup of boiling water. Allow it to cool, then filter. Dip a compress in the solution and apply on the swollen area, including the scalp.
To avoid possible ill-effects, always test the hair dye on your skin before dyeing your hair. The skin test is made on the skin on the inside pf the arm at the elbow, or at the back of the neck. Apply test dye on a clean skin and allow it to dry for a few minutes, then make a second application. Wait for the result for 48 hours. It does happen quite frequently that a hair-dresser or beautician will dye your hair without a skin test, afraid of losing a customer. So it is up to you to insist on this test. Remember, you should not go on a chemical hair dye, if—
(a) You had an itching of the scalp at the time of the previous dye,
(b) You suffer from asthma,
(c) You have had or at present have eczema or urticaria on any part of your body,
(d) You suffer from kidney complaint,
(e) You have any sort of skin problem,
(f) You are pregnant,
(g) You have hair in bad condition and excessively dry,
(h) You are feeding a baby,
(i) You have menses.
