What can be done for my 4yo son who got infected by herpangina?

HERPANGINA: It is a coxsackie virus infection with painful lesions in the pharyngeal mucosa and high fever. Treatment is symptomatic , heals in few days.

Viral infection: Herpangina is a viral illness that involves ulcers and sores inside the mouth, a sore throat, and fever. It is a common childhood infection. Most often seen in children ages 3 - 10, but it can occur in any age group. Tylenol (acetaminophen) or Motrin to control fever. Increase fluid intake to prevent dehydration. Eat a non-irritating diet. Use topical anesthetics for the mouth. It usually clears up in a week.

Keep hydrated: The big problem with these kids is getting them to drink/swallow. Chilled fluids, chilled applesauce or similar things help some. Sometime a mixture of Benadryl & milk of magnesia (equal parts of each) can be used as a gargle/spit out med to coat the sores & provide temporary relief. Chilled pediasure can provide nutrients. If you can keep him hydrated he will heal in a week or so.