This pattern is classified as ‘Exterior’ not because it derived from an external pathogenic factor but because its manifestations are located in the ‘Exterior’ of the body such as the skin, muscles and Channels.

The Defensive Qi reacts to the external Heat Evil and the battle between the two gives rise to 'fever'. The fever here does not necessarily indicate an actual fever, but rather the patients' objective feeling of the heat. The Aversion to cold is the consequence of this fever.

This pattern is quite similar to Exterior-Cold, but with Heat related manifestations. The main difference is the feeling of thirst and slightly sweating. Dryness often accompanies Heat, hence the symptoms of feeling thirst. There is no Cold Evil constraining the skin pores, therefore the patients sweat slightly.

The Heat also goes up to the Head and causes headache and red tongue. However, the redness is on the tip or on the sides, which indicates the Exterior feature of the pattern.