Diagnosaurus
- Paget's disease of bone
- Pain, anorectal
- Pain, chronic
- Pain syndrome, complex regional
- Palsy, Bell's
- Pancreatic cancer
- Pancreatitis, acute
- Pancreatitis, chronic
- Pancytopenia
- Panic disorder
- Papillary necrosis
- Papilledema
- Paragonimiasis
- Paraneoplastic syndromes
- Parasites involving the lung
- Parasomnias
- Parathyroid hormone deficiency
- Parathyroid hormone excess
- Parkinsonism
- Paronychia
- Parotid gland swelling
- Parvovirus infection
- Patellofemoral syndrome
- Patent ductus arteriosus
- Pauci-immune glomerulonephritis
- PCP
- PDA
- PEA
- Pediculosis
- Pelvic inflammatory disease
- Pemphigoid, bullous
- Pemphigus vulgaris
- Peptic ulcer disease
- Perforated septum
- Perianal fistula
- Pericardial effusion
- Pericarditis
- Pericarditis, constrictive
- Periodic paralysis syndrome
- Peripheral neuropathy (mononeuropathy)
- Peripheral neuropathy (polyneuropathy)
- Peritonitis
- Peritonsillar abscess
- Personality disorder
- Pertussis
- Pesticide exposure
- Pharyngitis
- Pharyngitis, streptococcal
- Pheochromocytoma
- Phobic disorder
- Phosphate, decreased serum
- Phosphate, increased serum
- Photodermatitis
- PID
- Pinworm infection
- Pituitary hormones decreased
- Pityriasis rosea
- Pityriasis versicolor
- Plague
- Plantar fasciitis
- Platelet count, increased
- Platelet disorders, qualitative
- Pleural effusion
- Pleural plaques (masses or thickening)
- Pleuritis (pleurisy)
- PMS
- Pneumococcal pneumonia
- Pneumoconiosis
- Pneumocystis pneumonia
- Pneumonia, anaerobic
- Pneumonia, community-acquired
- Pneumonia, eosinophilic
- Pneumonia, hospital-acquired
- Pneumonia, recurrent or persistent
- Pneumothorax
- Podagra
- Poisoning syndromes
- Poliomyelitis
- Polyarteritis nodosa
- Polychondritis, relapsing
- Polycystic kidney disease
- Polycystic ovary syndrome
- Polycythemia
- Polycythemia vera
- Polymyalgia rheumatica
- Polymyositis
- Polyps of colon and small intestine
- Pomphylox
- Porphyria, acute intermittent
- Porphyria cutanea tarda
- Portal hypertension
- Potassium, decreased serum
- Potassium, increased serum
- Pott's disease
- Preeclampsia
- Pregnancy
- Pregnancy, ectopic
- Premature ovarian failure
- Premenstrual syndrome
- Pressure sores
- Primary biliary cirrhosis
- Primary sclerosing cholangitis
- Prion disease
- Prolactin, increased
- Prolactinoma
- Prostate cancer
- Prostatic hyperplasia, benign
- Prostatitis, acute bacterial
- Prostatitis, chronic bacterial
- Prostatitis, nonbacterial
- Protein-losing enteropathy
- Proteinuria, microalbuminuria
- Proteinuria, nephrotic syndrome
- Prothrombin time, increased
- Pruritus, anogenital
- Pseudogout
- Pseudomembranous colitis
- Pseudotumor cerebri
- Psittacosis
- Psoriasis
- Psoriatic arthritis
- Psychosomatic disorder
- Psychotic disorder
- PT increased
- Pulmonary alveolar proteinosis
- Pulmonary disease, occupational
- Pulmonary edema, acute
- Pulmonary embolism
- Pulmonary fibrosis, idiopathic
- Pulmonary hemorrhage
- Pulmonary hypertension
- Pulmonary insufficiency
- Pulmonary parasites
- Pulmonary-renal syndromes
- Pulmonary-sinus syndromes
- Pulmonary stenosis
- Pulmonary thromboembolism
- Pulseless disease
- Pulseless electrical activity
- Purpura, idiopathic thrombocytopenic
- Purpura, thrombotic thrombocytopenic
- Pyelonephritis
- Pyoderma gangrenosum