1) Affected by diphtheria 2) Pertaining to diphtheria 
• (a.) Having characteristics resembling those of diphtheria; as, diphtheritic inflammation of the bladder. • (a.) Pertaining to, or connected with, diphtheria.
Pertaining to a false membrane often covering a lesion in the intestine or lung passages, formed by the solidification of secretions from the lesion.
Diph`the·rit'ic adjective (Medicine) 1. Pertaining to, or connected with, diphtheria. 2. Having characteristics resembling those of diphtheria; as, diphtheritic inflammation of the bladder. 
pertaining to diphtheria. · affected by diphtheria.