An extra 3.2m households across the UK bought a pet between 2020 and 2021 during the pandemic, with many taking the opportunity to get a dog while working from home.
The subsequent cost-of-living crisis meant owners struggled to buy pet food and cover medical bills including simple treatments, Ms Cartwright said.
“We are seeing dogs coming in bald with mange that are taking a lot of time to get back healthy which again bed-blocks,” she added.
The charity relies on donations and needs, Ms Cartwright says, between £30,000 and £40,000 each month to keep running.
But with a long waiting list, Ms Cartwright said the charity faced “really tough decisions” in the future if dogs came in with a need for several years of therapy.
“We are going to have to start to look at [whether] we can justify that time,” she warned.