My son has diphtheria, how long until he can return to school?

Finish RX & neg test: Patients with pharyngeal diphtheria are considered potentially contageous untill they have finished their antibiotic rx and had 2 negative cultures at least 24hrs apart.

Depends: If the diptheria is cutaneous then he must finish 10 days of antibiotic and have 2 negative cultures of the wound done within 24 then 48 hours of completing treatment. If the diptheria is throat, nasal or pneumonia then 10 days of antibiotic should be completed and 2 separate cultures of the nose and throat must be negative to be considered clear. All exposed cultured, quarantined 1 wk and treated.