Internal heat may cause cough, but not all coughs are due to internal heat.
Patients with internal heat may have high fever, red face, thirst and coldness, yellowish red urine and constipation.
If the internal heat involves the lungs, there may be fever, thirst, cough, shortness of breath, coarse breathing, severe nasal flutter, nosebleed; or dry cough without sputum, or sputum is small and sticky, not easy to cough out, or blood in the sputum, hoarseness, severe loss of voice, dry mouth and throat, emaciation, and five heart-heat (heat in the hearts of the two hands and feet, and self-consciousness of the heart and chest (irritability and sultriness)), and other symptoms.
If you have a cough, it is recommended that you seek medical attention. There are many reasons for coughing, so you should consult your doctor.