Carbuncle, called suppurative lymphadenitis in western medicine, implies obstruction of qi and blood by pathogenic toxins and can be divided into "internal carbuncle" and "external carbuncle". Internal carbuncle occurs in zang-fu organs and external carbuncle occurs on the body surface.

External carbuncle refers to acute suppurative disease happening between the skin and flesh. It is believed in Chinese medicine that this disease is mostly caused by lesion of the skin and mucous membrane, failure of weidefensive qi and infection of pathogenic toxins. Its clinical features are shining and non-tipped carbuncle in the local area, with red color, swelling and pain (no change in skin color in fewer cases), swift onset, easy to swell,easy to suppurate, easy to ulcerate and easy to astringe,mostly accompanied by obvious general symptoms. Due to difference in the locations, there are many names. For instance, carbuncle happening in the neck is called neck carbuncle.

Carbuncle occurring underneath the armpit is called axillary carbuncle. Carbuncle occurring in the inguinal groove is called hip and abdominal carbuncle. Carbuncle happening in the area of Weizhong (BL 40) is calledWeizhong toxin. There are also other types, such as breast carbuncle. Because of difference in the treatment and prognosis, breast carbuncle will be explained in the chapter of mammary diseases. This disease is similar to acute suppurative lymphadenitis.