As with many pedigree dogs, genetic diseases have increased in the Shar Pei since the 1980s. Allergies are also very common. In addition to the Shar Pei's specific CNV situation, there are other reasons for this general deterioration. The main reason is considered by scientists to be the pure breed dogma in modern pedigree dog breeding. Especially with regard to the fact that the genetic variance in the western Shar Pei is very low, since the modern western Shar Pei breed already started in a very narrow genetic bottleneck situation. The population could be increased from a very small number of animals to many thousands today, but the genetic variance can never be increased in this way.
In the Chinese Shar Pei, allergies are unknown, although there will of course be dogs that have an allergy. The causes may be due to the fact that the genetic variance of the Shar Pei population in China is much greater than it is in the west, and also because breeders there like to look for dogs in the countryside with which the gene pool can be expanded. And even if pure breeding is very important in China, there are more new genetic variances.