The Scottish SPCA has launched an investigation after the almost skeletal female was handed in to the charity base in Dundee last week, covered in painful sores.
A spokesman for the charity said: "The seven-year-old female crossbreed was brought to Brown Street kennels on Wednesday by a man who claimed he was handing her in on behalf of someone else. He said her name was Suzie.
"Staff were alarmed by Suzie's condition and contacted the local dog warden to arrange for the dog to be taken to a vet clinic for treatment. We are now investigating the incident."
Karen Cooper, an SSPCA inspector, said: "She is covered in painful sores.
"We are not yet sure how she came to sustain these wounds, which will have been causing her a great deal of pain and discomfort. They could be from an untreated skin condition, pressure sores or possibly cigarette burns."
Suzie weighed only 4.3kg when she was brought in, which Ms Cooper said was about half the weight she should be.
She added: "No animal deserves to be treated in such a terrible way. She has clearly been starved of basic nutrition and denied veterinary treatment, causing her unnecessary suffering for weeks, possibly even months.
"We are appealing to anyone who recognises Suzie or knows who might have owned her to contact us."
The SSPCA spokesman said Suzie was now on a feeding programme to help her gain weight and receiving veterinary care at the charity's regional rescue and rehoming centre at Petterden, near Dundee.