Shaoyin diseases may be due to direct attack of the Shaoyin by exogenous pathogenic factors when the body has yang deficiency and cold; or due to the transmission of pathogenic factors from other channels into the Shaoyin; or due to treatment employing a strong diaphoretic action that injures the yang. After invasion of the Shaoyin by pathogenic factors causing yin symptoms, a change into cold may occur. If yang symptoms occur they may transform into heat. Therefore Shaoyin diseases can be divided into Shaoyin syndromes of cold transformation and Shaoyin syndromes of heat transformation.

Cold transformation Shaoyin syndromes
Aversion to cold, sleeping with the knees drawn up, listlessness, cold extremities, loose stool with undigested food, vomiting, absence of thirst, preference for hot drinks, profuse and clear urine, pale tongue with white coating, deep and feeble pulse.

Shaoyin syndromes of cold transformation are the manifestations of heart and kidney yang deficiencies and interior retention of yin cold. Insufficient yang qi fails to warm and nourish the extremities resulting in cold extremities and sleep with the knees drawn up. Listlessness is due to the inability of yang qi to nourish the mind. Kidney yang deficiency is unable to warm the middle jiao leading to a dysfunction of the ascending and descending functions of middle jiao qi, resulting in loose stool with undigested food and vomiting. Yang deficiency unsuccessfully controls water, so there is profuse and clear urine. Absence of thirst, preference for hot drinks, pale tongue proper with white coating, and deep feeble pulse are all signs of yang deficiency and yin preponderance.

Heat transformation Shaoyin syndromes
Irritability, insomnia, dryness of mouth and throat, red tongue tip or deep red tongue proper with scanty tongue coating, deep, thready, and rapid pulse.

The patient usually has a yin deficiency. After pathogenic factors invade the Shaoyin, they are liable to transform into heat affecting kidney yin. A lessening of kidney yin (body fluid) prevents its upward flow to the heart, and leads to hyperactivity of the heart fire. Symptoms of irritability, insomnia, dryness of the mouth and throat, deep red tongue, deep thready, and rapid pulse occur.