An allergic reaction occurs when the immune system, which is the body's normal defence against dangerous foreign substances, mistakes a normally harmless substance for an invader, such as a virus. No one knows why this abnormal reaction occurs in some people and not others.
People who have this type of unusual immune system are said to be hypersensitive. About one in twenty-five clients have some form of reaction to tints and a number of semi-permanents containing either phenylenediamine or para-toluenediamine. Product manufacturers recommend skin tests before every tint application.
Mix a small amount of tint with equal parts of peroxide (the strength you intend to use)
Cleanse either the inside of the elbow or behind the ear with cotton wool and spirit (alcohol)
Place a small smear of tint on the cleansed area and allow to dry naturally or cover with Nu-skin. (collodion)
Advise the client to leave the patch alone until returning to the salon, unless it begins to irritate, when it should be washed off and calamine lotion used to relieve the irritation.
If a positive reaction occurs, do not allow tint to come into contact with the clients scalp.