Fever in Cold Damage. How to elucidate it? Fever refers to the condition where heat is constrained within the skin and disseminates outward, manifesting as heat.
This differs from tidal fever (Tidal Fever) and alternating chills and fever (Alternating Chills and Fever), though they may seem similar. It resembles irritability (Irritability) but is not the same. Irritability indicates pathology located internally. The heat of tidal fever occurs at specific times, adhering to a regular schedule. The heat of alternating chills and fever manifests after chills subside, occurring sequentially. In contrast, general fever occurs without a fixed time pattern. Some describe "feather-like fever" (Feather-like Fever), while others describe "steaming bone fever" (Steaming Bone Fever); these differ in severity, distinguishing between exterior (Exterior) and interior (Interior) patterns.
"Feather-like fever" implies heat felt as if covered by feathers, indicating that the heat is in the exterior. Therefore, Guizhi Tang (Cinnamon Twig Decoction) is used to induce sweating and disperse it. "Steaming bone fever" implies heat rising like steam, indicating that the heat is in the interior. Therefore, Tiaowei Chengqi Tang (Stomach-Regulating Purging Decoction) is used to purge downward and cleanse it. Exterior-pattern fever results from wind-cold pathogens lodging in the skin, causing the obstruction of Yang Qi. Interior-pattern fever results from the sinking of Yang Qi into the Yin aspect. By observing the origin of the heat, one can verify the differentiation through methods of sweating or purging. If heat originates first from the skin, it indicates the pathogen is in the exterior. If heat originates internally and then spreads to the surface, it indicates the pathogen is in the interior. These two examples illustrate fever caused by pathogens in the exterior or interior. Since fever occurs in both exterior and interior patterns, patients with pathogens in the half-exterior half-interior (Half-Exterior Half-Interior) also present with fever. Why? Because the exterior syndrome has not yet resolved, and the pathogen has transmitted inward, but the interior has not yet formed excess accumulation; this state is defined as half-exterior half-interior. The fever may start from the skin and gradually transmit to interior heat, or start as internal heat and reach outward to the exterior. Generally, when pathogens are in the exterior causing fever, there is exterior heat but no interior heat. When pathogens are in the interior causing fever, interior heat is severe and extends to the exterior. When pathogens are in the half-exterior half-interior causing fever, both exterior and interior exhibit heat, though the intensity is milder than in pure exterior cases. Although the classics state: "Fever with aversion to cold indicates onset in Yang channels; absence of fever with aversion to cold indicates onset in Yin channels," Shaoyin disease (Shaoyin Disease) upon initial onset may also present with counter-flow fever. This too belongs to the exterior category, treated specifically with Mahuang Xixin Fuzi Tang (Ephedra, Asarum, and Aconite Decoction) to induce sweating. Fever is associated with Yang and is common in cold diseases. However, when both Yin and Yang are deficient, or following diarrhea or recent sweating, fever becomes undesirable. The classics state: "If pulses at all positions are deficient and fever persists, death ensues. Diarrhea accompanied by fever also leads to death." The *Neijing* states: "Sweating followed immediately by recurrent fever, with rapid and restless pulses that do not diminish due to sweating, accompanied by delirium and inability to eat, is named 'Yin-Yang Intersection' (Yin-Yang Jiao). Intersection signifies death." This is also a form of fever. How can it be discussed indiscriminately alongside ordinary fever? Physicians must distinguish it clearly.