With September comes the ‘Back to School’ season, and students’ fill their pencil cases with all the essentials – pens, pencils, rubbers, rulers. These are readily accessible to pets and dogs (and other animals!) may chewing and eat various stationery items. The majority of pencil case-fillers are considered ‘non-toxic’, and mostly pose an obstruction risk, for example rubber erasers, rulers and elastic bands. Two items we receive calls about that are often more of a worry to owners and vets, are pens and pencils.
Contrary to what many people believe, pencils do not contain lead. Rather, the core is made up of the non-toxic mineral, graphite. The common name “pencil lead” is due to an historic association with the stylus made of lead in ancient Roman. As with the stationery discussed above, pencils are more of an obstruction and perforation risk, especially when chewed and sharp, than a toxicological risk.
Another common concern is when pens are ingested by animals, including felt tip pens, and their ink. The tip of these pens is made of felt (or sometimes an absorbent plastic). The ink reservoir feeds ink through the felt tip and onto the writing surface. The ink in felt tip pens is of low toxicity and the volume is low, therefore systemic toxicity is not expected. The possible clinical signs of ingestion include hypersalivation and vomiting, as well as discolouration of the tongue and/or mouth. The plastic pieces of a pen are a potential foreign body hazard.