From the beginnings of Chinese medicine, over 2000 years ago, theories of disease causes and treatment methods evolved, many of which are still used today.
Concerns with specific skin conditions can be traced back to the 14th century BC. For example, the word 疥 jiè–scabies, an extremely itchy parasitic infection–is found inscribed on the tortoise shells used during the Shang dynasty for divination.
But Chinese records show that as early as the 11th century BC medicine had already specialised into four areas: diet, acute diseases, external and skin, and veterinary medicine.
The earliest writings on the theory of skin diseases is found in the Yellow Emperor’s Classic from the third century BC, and by the second century AD there were extensive written records describing a wide variety of skin disorders and their treatments.
The Taiping Era Recipes of Sagely Compassion published in 992AD emphasised the importance of addressing the whole situation of the patient in regards to diagnosis and treatment, not just looking at the skin without regard to the rest of the body, mind and social milieu of the patient.
The dermatological field flourished during the Ming and Qing Dynasties (1368-1840), with the publication of various books solely devoted to external diseases, such as Chen Shi-Gong’s Orthodox Lineage of External Medicine in 1617 and Qi Kun’s Great Compendium of External Medicine published in 1665.
In 1604, Shen Dou-Yuan wrote Profound Insights on External Diseases and this was considered China’s first atlas of skin diseases.
Here is an on-line article with more.