Colophony: Rosin in unmodified and modified form

Abstract

Colophony (rosin) is a common cause of contact allergy and allergic contact dermatitis (ACD). Rosin is present in unmodified and modified form in many products with various usages and is ubiquitous in our daily life. Due to this, contact with rosin or rosin derivatives in commercial products is difficult to detect. Main usages are printing ink, adhesives, and sealants as well as paper size (2008). Rosin/colophony has an EU harmonised classification as skin sensitizing according to Annex VI of the CLP regulation (Regulation (EC) No 1272/2008). This means that the hazard statement H317 « May cause an allergic skin reaction » or the risk phrase R43 “May cause sensitisation by skin contact” shall apply for products containing rosin in a concentration of at least 1%. The allergenicity of modified rosins can be caused by new allergenic derivatives, specifically maleopimaric acid, but also due to unmodified rosin still present after modification. More investigations with regard to the presence of various modified rosins in different products are needed. Studies on the prevalence of ACD in dermatitis patients and in the population caused by modified rosins should be performed.