S
- Sacral dimple
- Sacroiliitis
- SAD
- Salivary gland tumors
- Salmonella infection
- Salmonellosis
- Sarcoidosis
- Sarcoma
- Sarcoma, bone cancer
- Sarcoma, soft tissue
- SBBO
- Scabies
- SCAD
- Scalded mouth syndrome
- Scarlatina
- Scarlet fever
- Schizoaffective disorder
- Schizoid personality disorder
- Schizophrenia
- Schizophrenia, adolescent
- Schizophrenia, childhood
- Schizophrenia, juvenile
- Schizotypal personality disorder
- Schwannoma
- Schwannomatosis
- SCI
- Sciatica
- Scleroderma
- Sclerosing cholangitis
- Sclerosing mesenteritis
- Sclerosis, multiple
- Sclerosis, systemic
- Scoliosis
- Scorpion sting
- Scrotal masses
- Seasonal affective disorder (SAD)
- Seasonal allergy
- Sebaceous carcinoma
- Sebaceous cysts
- Seborrheic dermatitis
- Seborrheic keratosis
- Secondary brain cancer
- Secondary hypertension
- SEID
- Seizure disorder
- Seizure, absence
- Seizure, febrile
- Seizure, grand mal
- Seizure, petit mal
- Seizure, temporal lobe
- Seizures
- Selective IgA deficiency
- Self harming
- Self-injury/cutting
- Separation anxiety disorder
- Sepsis
- Septal defect, atrial
- Septal defect, atrioventricular
- Septal defect, ventricular
- Septic arthritis
- Serotonin syndrome
- Severe acute respiratory syndrome
- Severe acute respiratory syndrome (SARS)
- Severe brain injury, coma
- Sex headaches
- Sexual dysfunction, female
- Sexual obsession
- Sexually transmitted diseases (STDs)
- Sezary disease
- Sezary syndrome
- Shaken baby syndrome
- Shellfish allergy
- Shigella infection
- Shin splints
- Shingles
- Short bowel syndrome
- Shoulder dislocation
- Shy-Drager syndrome
- SIBO
- Sick sinus syndrome
- Sickle cell anemia
- SIDS
- Sin Nombre virus infection
- Sinus headaches
- Sinusitis, acute
- Sinusitis, chronic
- Sjogren’s syndrome
- SJS
- Skin cancer
- Skin cancer, melanoma
- Skin writing
- Skin, itchy
- Skipped heartbeats
- Skull base tumors
- Slapped cheek disease
- Sleep apnea
- Sleep apnea in children, obstructive
- Sleep apnea, central
- Sleep apnea, obstructive
- Sleep disorders
- Sleep terrors (night terrors)
- Sleepiness, daytime
- Sleeplessness
- Sleepwalking
- Slipped disk
- SLL
- Slow heartbeat
- Small bowel bacterial overgrowth
- Small bowel cancer
- Small bowel prolapse
- Small bowel prolapse (enterocele)
- Small intestinal bacterial overgrowth (SIBO)
- Small intestine prolapse
- Small lymphocytic lymphoma
- Small vessel disease
- Smallpox
- Snoring
- Social anxiety disorder (social phobia)
- Soft palate cancer
- Soft tissue sarcoma
- Solar keratosis
- Solar lentigines
- Solitary fibrous tumor
- Solitary rectal ulcer syndrome
- Somatic symptom disorder
- Somnambulism
- Sore throat
- Spasmodic torticollis
- Specific phobias
- Specific reading disability
- Spermatocele
- Spider bites
- Spina bifida
- Spinal arteriovenous malformation (AVM)
- Spinal cord injury
- Spinal cord tumor
- Spinal curvature
- Spinal fluid leak
- Spinal headaches
- Spinal stenosis
- Spinal tumor and spinal mass
- Splenomegaly
- Spondylosis, cervical
- Spontaneous coronary artery dissection (SCAD)
- Sprained ankle
- Sprains
- Squamous cell carcinoma of the skin
- Stage 4 (metastatic) colon cancer
- Stage 4 prostate cancer
- Stammering
- Staph infections
- STDs
- Steele-Richardson-Olszewski syndrome
- Stein-Leventhal syndrome
- Stenosing tenosynovitis
- Stenosis, aortic valve
- Stenosis, mitral valve
- Stenosis, pulmonary valve
- Stenosis, pyloric
- Stenosis, spinal
- Stevens-Johnson syndrome
- Stings, bee
- Stings, jellyfish
- Stings, scorpion
- Stomach cancer
- Stomach flu
- Stomach polyps
- Stomatodynia
- Stool holding
- Strawberry hemangioma
- Strep throat
- Stress cardiomyopathy
- Stress fractures
- Stress incontinence
- Stretch marks
- Stroke
- Stump pain
- Stuttering
- Stye (sty)
- Subarachnoid hemorrhage
- Subconjunctival hemorrhage (broken blood vessel in eye)
- Subfertility
- Substance abuse disorder
- Substance use disorder
- Sudden cardiac arrest
- Sudden infant death syndrome (SIDS)
- Suicide
- Suicide and suicidal thoughts
- Sun allergy
- Sun poisoning
- Sunburn
- Sunken chest
- Supranuclear palsy
- Supraventricular tachycardia
- Suspicious breast lumps
- SVT
- Sweating and body odor
- Sweating, abnormally excessive
- Swelling
- Swimmer’s ear
- Swimmer’s itch
- Swollen knee
- Swollen lymph nodes
- Syndrome X
- Synostosis
- Synovial sarcoma
- Syphilis
- Syringomyelia
- Systemic exertional intolerance disease
- Systemic lupus erythematosus
- Systemic mastocytosis
- Systemic sclerosis