The Portuguese Water Dog is a fairly rare breed; only 36 Portuguese Water Dogs were entered for Britain's Crufts competition in 2013. Though some breeders claim they are a hypoallergenic dog breed, there is no scientific evidence to support the claim that hypoallergenic dog breeds exist. Their non-shedding qualities have made them more popular in recent years. If left untended, the hair on a PWD will keep growing indefinitely. Problems associated with this include the hair around the eyes growing so long as to impede vision, and matting of the body hair, which can cause skin irritations. For these reasons, PWDs must be trimmed about every two months and the coat brushed every other day.