Pharyngitis does not turn into hand, foot, and mouth disease. Although both are caused by viral infections and both can present with symptoms of oropharyngeal herpes at the onset, they are different diseases and are not necessarily related. Pharyngitis is usually caused by infection with Coxsackie virus, Clostridium difficile, EBV, and Streptococcus hemolyticus. Infections are mostly associated with decreased immunity, including wasting diseases (such as malignancy), malnutrition, exertion, and taking drugs that suppress immune function. In addition, leukemia can also cause damage to the mucosal tissue of the pharyngeal isthmus and cause an inflammatory response. HFMD is caused by a variety of enterovirus infections that invade the body through the respiratory or digestive tract, among which coxsackievirus A16 and enterovirus 71 infections are the most common. After infecting the human body, enteroviruses can replicate in large numbers in the tonsils, pharynx and lymph nodes of the intestine, and then release into the blood, further spreading to the skin and mucous membranes, nervous system, respiratory system, heart, liver, pancreas and adrenal glands, causing a series of inflammatory reactions in the corresponding tissues and organs, and leading to the corresponding clinical manifestations. In summary, pharyngitis and HFMD are different diseases, and there is no conversion of pharyngitis to HFMD. Patients with pharyngitis or HFMD are advised to actively seek medical attention to improve their prognosis.