The hardness behind the ear is considered to be related to the protrusion of bones behind the ear, or the presence of swollen lymph nodes behind the ear, folliculitis behind the ear and other diseases. 1. Protruding bones behind the ear: For some people with thin physique, the soft tissues behind the ear may be weak, resulting in protruding bones behind the ear. When the patient touches the protruding part of the bone, the feeling of hardness behind the ear may appear. 2. Enlarged lymph nodes behind the ear: Enlarged lymph nodes behind the ear can be seen in head and face infections or non-infectious diseases. When the stimulation of disease-causing factors leads to the enlargement of multiple lymph nodes behind the ear or the lymph nodes are fused and adhered together, this clinical symptom of hardness behind the ear can also be triggered. 3. Behind-the-ear folliculitis: behind-the-ear folliculitis is usually seen in bacterial infections, bacterial infections caused by inflammation can stimulate the skin behind the ear, resulting in excessive swelling of the skin triggering hardness behind the ear this clinical symptom. Because of the cause of hardness behind the ear, it is recommended to actively seek medical attention to identify the cause of the disease, according to the doctor’s instructions for treatment.