- Perinephritic - see condition
- Perinephritis (see also Infection, kidney) 590.9
- Perineum, perineal - see condition
- Perineuritis NEC 729.2
- Periodic - see also condition
- Periodontal
- Periodontitis (chronic) (complex) (compound) (simplex) 523.40
- Periodontoclasia 523.5
- Periodontosis 523.5
- Periods - see also Menstruation
- Perionychia (with lymphangitis) 681.9
- Perioophoritis (see also Salpingo-oophoritis) 614.2
- Periorchitis (see also Orchitis) 604.90
- Periosteum, periosteal - see condition
- Periostitis (circumscribed) (diffuse) (infective) 730.3
- Periostosis (see also Periostitis) 730.3
- Peripartum cardiomyopathy 674.5
- Periphlebitis (see also Phlebitis) 451.9
- Peripneumonia - see Pneumonia
- Periproctitis 569.49
- Periprostatitis (see also Prostatitis) 601.9
- Perirectal - see condition