My son is 3.5 years old and weighs 14 kg. Was having a repetitive condition of pain and stiffness behind left ear with fever and cough and cold. Which was diagnosed as left cervical lymphadenitis the condition is repeating after almost a month. And has repeated fourth time. He has been on antibiotics like zifi for 3 or 5 days. And on the last occasion linezolid for 14 days. But it has again repeated with same symptoms. A little worried wants to seek expert advice. Please help.