In infancy, lymph nodes are immature and the barrier effect is weak. Local slight infection can make lymph nodes red and swollen or even purulent, leading to cellulitis around lymph nodes. Direct invasion of bacteria or inflammation in drainage area are common causes of inflammation and swelling of lymph nodes. Retroauricular lymphadenopathy can be seen in viral diseases such as rubella virus infection, as well as head furuncle or eczema. The possibility of infectious diseases, systemic infections such as measles, chickenpox, infectious mononucleosis and hematological diseases should be considered when lymph nodes in superficial parts of the whole body are enlarged.
In addition, the retroauricular protuberance may also be a cyst or abscess. For example, acute suppurative otitis media may be complicated with retroauricular subperiosteal abscess. Congenital preauricular fistula with infection can also appear local swelling; The first branchial cleft cyst can also be manifested as a superficial cyst in front of or behind the baby's ear. When the child is found to have swelling behind the ear, he should go to the hospital in time to confirm whether it is lymph node enlargement or other reasons, and treat it according to the cause.