If a patient has a painful swelling behind the ear, acute retroauricular lymphadenitis is the main cause. It is often caused by the lymph nodes behind the ear after the patient has become anxious and inflamed, or after acute pharyngitis or acute tonsillitis. The main symptom of the patient is that the pain is particularly pronounced, and sometimes even dare not do the chewing action, in terms of treatment must be actively anti-inflammatory. Patients who are not allergic to cephalosporin can take oral cefdinir dispersible tablets, or cefdinir capsules. If the patient’s pain is unbearable, infusion therapy can also be considered if necessary. Cefuroxime sodium injection is commonly used clinically, and a skin test is required before administration. Bactrim cream can be applied locally behind the ear, which can effectively play an anti-inflammatory and anti-swelling role. Normally, the patient’s condition will improve significantly after a week or so of active treatment.