Hot and Cold describe the nature of a pattern, and their associated symptoms depend on whether they are combined with a Excess or Deficient condition.
Full Heat can be Exterior (as in Wind-Heat) or Interior. The symptoms of invasion of Wind-Heat have already been described in the page on the Interior. Full Heat (whether external or internal) is a manifestation of Excessive Yang.
The main symptoms of Full Heat in an Interior condition are thirst, a feeling of Heat, some mental restlessness, red face, dry stools, scanty dark urine, a Rapid-Full pulse, and a Red tongue with yellow coating.
Beyond these, it is difficult to generalize as other symptoms will depend on the Organ affected. Aside from the above symptoms, there are other diagnostic guides which indicate Heat. Any raised, red skin eruption which feels hot indicates Heat. As for pain, any burning sensation indicates Heat: for example, the burning sensation of cystitis, or a burning feeling in the stomach. Any loss of Blood, with a large quantity of dark-red Blood, indicates Heat in the Blood. As far as the Mind is concerned, any condition of extreme restlessness or manic behavior indicates Heat in the Heart.
Interior Full Heat may derive directly from the excessive consumption of hot-energy foods (e.g. red meats, spices and alcohol) or, indirectly, from emotional stress.
In fact, emotional stress tends to cause Qi Stagnation in its early stages; if Qi Stagnates for some time, it usually gives rise to some Heat. With further passage of time, Heat may turn into Fire. Finally, Interior Full Heat may also derive from the transformation of a pathogenic factor which penetrates the Interior and turns into Heat as it does so.
From the Yin–Yang point of view, Empty Heat arises from a Deficiency of Yin. If the Yin energy is Deficient for a long period of time, the Yin is consumed and the Yang is relatively in Excess. Please note that Yin may be Deficient for years before giving rise to Empty Heat. Therefore, Empty Heat always derives from Yin Deficiency but a patient can very much suffer from a Yin Deficiency without Empty Heat. The tongue will show the difference clearly: in Yin Deficiency, the tongue lacks a coating but it has a normal color; in Yin Deficiency with Empty Heat, the tongue lacks a coating and is red.
The main general manifestations of Empty Heat are a feeling of Heat at the end of the day, a dry mouth with desire to drink in small sips, a dry throat at night, night sweating, a feeling of heat in the chest and palms and soles (also called ‘five-palm heat’), dry stools, scanty dark urine, a Floating-Empty and Rapid pulse and a Red tongue without coating.
Again, these are only the general symptoms and signs; others depend on which Organ is mostly affected. Empty Heat frequently arises from Kidney Yin Deficiency. Because Kidney Yin is the foundation for all the Yin energies of the body, when this is Deficient, it can affect the Yin of the Liver, Heart and Lungs. A long-standing Yin Deficiency in any of these Organs can give rise to Empty Heat manifesting with various symptoms, such as mental restlessness and insomnia when Heart Yin is Deficient, irritability and headaches when Liver Yin is Deficient and dry cough when Lungs Yin is Deficient.
Aside from these manifestations, from a mental–emotional point of view Empty Heat can often lead to a feeling of mental restlessness, fidgeting and vague anxiety. The patient feels that something is wrong but is unable to describe what or how. Empty Heat restlessness is quite different from that of Full Heat and one can almost visually perceive the Emptiness underlying the Heat.
In practice, it is important to differentiate Full Heat from Empty Heat as the treatment method in the former case is to clear the Heat, while in the latter case it is to nourish Yin.
It is worth noting also that Empty Heat is no less ‘real’ than Full Heat. The term ‘Empty’ in ‘Empty Heat’ may give the false impression that this is not ‘real’ Heat: in fact, Empty Heat produces as much Heat as Full Heat, albeit in different forms.
Empty Heat derives from Yin Deficiency: therefore the causes of Empty Heat are the same as those that cause Yin Deficiency. These causes are:
The most common situation in which there are manifestations of both Heat and Cold is when these patterns simply coexist. This is an extremely common situation in practice. For example, it is common for a person to suffer from Kidney Yang Deficiency (hence Empty Cold in the Kidneys) and Damp Heat in the Bladder, or Spleen Yang Deficiency and Liver Fire (with a red face and thirst).
In some cases there may be contradictory Heat and Cold signs and symptoms, one of them being due to a ‘false’ appearance. This usually only happens in extreme conditions and is quite rare. It is important not to confuse this phenomenon with common situations when Heat and Cold are simply combined, as described right above.
For example, it is perfectly possible for someone to have a condition of Damp Heat in the Bladder and Cold in the Spleen. This is simply a combination of Heat and Cold signs in two different Organs, and does not fall under the category of False Heat and True Cold or vice versa.
In cases of False Heat and False Cold, tongue diagnosis shows its most useful aspect as the tongue-body color nearly always reflects the true condition. If the tongue-body color is Red it indicates Heat, if it is Pale it indicates Cold.
In some cases there is Heat above (as Heat tends to rise) and Cold below. The manifestations of this situation might be thirst, irritability, sour regurgitation, bitter taste, mouth ulcers (manifestations of Heat above), loose stools, Stomach rumbles and profuse pale urine (manifestations of Cold below).
The symptoms and signs would include a fever with aversion to cold, no sweating, a headache and stiff neck, aches throughout the body (manifestations of exterior Cold), irritability and thirst (manifestations of interior Heat).
This situation also occurs in attacks of Latent Heat combined with a new invasion of Wind-Cold. According to the theory of Warm diseases a person can be attacked by Cold in wintertime without developing any manifestations of it. The Cold can lie dormant in the Interior and change into Heat. In the Spring, with the rising of Yang energy, the interior Heat may be pulled towards the Exterior, especially in combination with a new attack of Wind-Cold. Because of this, the person would have symptoms and signs of an attack of Wind-Cold, but also signs of Interior Heat such as a thirst, irritability and a rapid pulse.
This situation simply occurs when a person with a Interior Cold condition is attacked by Exterior Wind Heat evil. There will therefore be some symptoms of Exterior invasion of Wind-Heat (such as a fever with aversion to cold, a sore throat, thirst, a headache and a Floating-Rapid pulse) and some symptoms of Interior Cold (such as loose stools, chilliness and profuse pale urine).