Allergenic reactions are due to the contact between the skin and some allergenic factors, which, in the case of fabrics, derive from the chemical substances used to dye the textile. Some elements of the so-called disperse dyes’ class are particularly prone to provoke intense allergenic reactions when deeply and long in contact to skin.
Why disperse dyes cause allergic reactions?
Disperse dyes are small molecules: their hydrofobic nature allows them to penetrate into a highly crystalline and hydrofobic fibre and dye it.
As they are small molecules they tend to get out of the fiber; thank to its hydrofobic character the skin in contact to the fabric tends to absorb the dye, especially in those part of body where the rubbing is significant. If the absorbed disperse dye is one of those classified as “allergenic” it is possible that an allergic reaction will appear on skin. The allergic reaction is more probable if some conditions are present: sweating, friction, and overweight.
When disperse dyes are used? Fabrics made totally or partially of polyester and acetate are certainly dyed with disperse dyes. Particularly polyester fabrics may have serious problems with color discharging by rubbing or washing, because of an abnormal quantity of oligomers present on the fiber (read more).
What to do to reduce the risk of skin reactions?
In order to avoid some drawbacks from fabrics (allergenic disperse dyes, but not only) you could wear only white or pale coloured fabrics.Anyway always wash your new garments before wearing them!