Many different types of allergic reactions developing at the site of tattoos have been recorded. Many pigments or dyes have been used in tattooing the different colors into the skin. The most commonly reported reactions have been sensitivity reactions due to mercury. Cinnabar which is red mercuric sulfide, also known as vermilion or Chinese red, is almost always used to produce the red color of tattoos. It is a brilliant red powder which is insoluble in water and dilute acids and is prepared by a process of sublimation of sulfur and mercury. Cadmium selenide (cadmium red) and sienna (ferric hydrate) are also used for red colors.
Different authors1-5 have attempted to categorize the various types of tattoo reactions. Fundamentally, they have been grouped into 5 different types of reaction.
The first reaction to be considered is the acute constant inflammatory reaction associated with physical tissue injury. This usually subsides