Health Library

Articles In This Section

• A to Z: Wolff-Parkinson-White (WPW) Syndrome

  Learn about Wolff-Parkinson-White Syndrome, a congenital heart condition that can cause an abnormally fast heart rhythm known as supraventricular tachycardia.

• A to Z: Wound Dehiscence

  Wound dehiscence is a condition where a cut made during a surgical procedure separates or ruptures after it has been stitched back together.

• A to Z: XXY Syndrome

  Learn genetic disorders and conditions that can affect social and sexual development.

• A to Z: Xerophthalmia

  Learn about this conditions that causes dry eyes.

• A to Z: Yellow Fever

  Learn about viral infections and diseases that can be transmitted from mosquitoes to humans.

• A to Z: Yersinia Enterocolitis

  See: Yersiniosis.

• A to Z: Yersiniosis

  Learn more about bacterial infections and illnesses that result from improper food preparation.

• A to Z: Zika Virus

  Zika is a virus that a person can get from being bitten by an infected mosquito. The virus is of particular concern for pregnant women and women who may become pregnant.

• A to Z: Zona

  Learn about viral infections and causes of skin conditions.

• A to Z: Zoonosis

  Learn more about diseases, infections, and conditions transmitted to humans from animals.

• A to Z: Vaginitis

  Vaginitis is an inflammation of the vagina.

• A to Z: Vaginosis

  Bacterial vaginosis (BV) is an infection in the vagina.

• A to Z: Vaginosis, Bacterial

  Bacterial vaginosis (BV) is an infection in the vagina.

• A to Z: Varicella (Chickenpox)

  Learn about viral infections, contagious diseases, and diseases that cause skin rashes.

• A to Z: Varices

  Varices are swollen blood vessels that usually develop in the esophagus or stomach.

• A to Z: Varices, Esophageal

  See: Varices.

• A to Z: Varices, Scrotal

  See: Varicocele (Scrotal Varices).

• A to Z: Varicocele (Scrotal Varices)

  A varicocele is an enlargement of the veins in the scrotum.

• A to Z: Venom

  Venom refers to poisonous substances that are administered by an animal to its prey or enemy through a bite or sting. Depending on the species, its effects can range from mildly irritating to deadly.

• A to Z: Ventricular Septal Defect (VSD)

  Learn about congenital heart defects and conditions that affect the heart and circulatory system.

• A to Z: Ventricular Tachycardia

  Learn about ventricular tachycardia, a potentially life-threatening arrhythmia in which the heart beats too rapidly.

• A to Z: Vesicoureteral Reflux (VUR)

  Learn more about conditions and infections of the urinary tract and kidneys.

• A to Z: Viral Exanthem

  Learn about viral infections and causes of skin rashes.

• A to Z: Viral Infection

  A viral infection is a an infection caused by a virus (a type of germ).

• A to Z: Vitiligo

  Vitiligo is a loss of skin pigment that causes white spots or patches to appear on the skin.

• A to Z: Von Hippel-Lindau Disease

  Von Hippel-Lindau disease, or VHL, is a genetic disorder that causes blood vessels to grow abnormally.

• A to Z: Warts

  Learn about warts, skin growths caused by viruses of the human papillomavirus (HPV) family.

• A to Z: Wheezing

  A "wheeze" is a high-pitched whistling sound made when air flows through narrowed airways in the lungs.

• A to Z Symptom: Vertigo

  See Dizziness.

• A to Z Symptom: Vomiting

  Most cases of vomiting are due to viral gastroenteritis ("stomach flu") and can be managed at home with treatment to prevent dehydration.

• A to Z: Ulcerative Colitis

  Learn more about this inflammatory disease of the large intestine, or colon.

• A to Z: Umbilical Granuloma

  Learn about disorders related to the umbilical cord and issues that affect newborn babies.

• A to Z: Undescended Testicle

  Undescended testis is a condition in which one or both of a boy's testicles (testes) have not moved into their proper place in the scrotum.

• A to Z: Upper Respiratory Infection

  An upper respiratory infection (URI) can be caused by many viruses or bacteria. The common cold, croup, and sinusitis are all URIs.

• A to Z: Ureterocele

  Ureteroceles are caused by a birth defect in which the opening in the ureter is too small for urine to pass freely into the bladder.

• A to Z: Ureteropelvic (UP) Junction Obstruction

  Ureteropelvic junction obstruction is a partial or total blockage of the flow of urine in the area where a ureter attaches to a kidney.

• A to Z: Urinary Tract Infection (UTI)

  Learn about bacterial infections and conditions that can affect the urinary tract.

• A to Z: Urticaria (Hives)

  Learn about urticaria, the red raised bumps or welts on the skin that are commonly called hives.

• A to Z: Uveitis

  Learn more about conditions of the eyes and factors that may contribute to vision loss.

• A to Z: Uveitis, Anterior

  Learn more about conditions of the eyes and factors that may contribute to vision loss.

• A to Z: Ureitis

  Learn more about conditions of the eyes and factors that may contribute to vision loss.

• A to Z: Tonsillitis

  Tonsillitis is an inflammation of the tonsils, the fleshy clusters of tissue in the back of the throat.

• A to Z: Tooth Injury, Primary

  A primary tooth injury is an injury or damage to a child's primary (or "baby") tooth.

• A to Z: Tooth Injury, Secondary

  Secondary tooth injuries are injuries or damage to secondary or permanent teeth (also called "adult" teeth).

• A to Z: Torticollis

  Learn about this condition, which affects neck muscles.

• A to Z: Tracheitis

  Learn about tracheitis, a condition that affects the respiratory tract.

• A to Z: Transplant, Bone Marrow

  Learn more about this medical procedure in which damaged stem cells in the blood are replaced with healthy stem cells.

• A to Z: Trisomy 21

  See: Down Syndrome.

• A to Z: Truncus Arteriosus

  In the womb, a child's heart may develop a single large artery rather than separate aortic and pulmonary arteries. Learn about the condition here.

• A to Z: Tuberous Sclerosis

  Learn about this genetic disorder that causes noncancerous tumors to grow in many parts of the body.

• A to Z: Tethered Cord

  A tethered cord is when part of the spinal cord is attached inside the spinal canal, and the spinal cord is not able to move freely.

• A to Z: Stomatitis

  Learn about stomatitis, an inflammation of the mouth.

• A to Z: Strabismus

  Strabismus is when the eyes are not lined up correctly.

• A to Z: Strep Throat

  Strep throat, a painful throat infection, is common in kids and teens. It gets better quickly with antibiotic treatment.

• A to Z: Sturge-Weber Syndrome

  Learn about this genetic disorder that can cause a birthmark on the face called a port-wine stain, as well as other symptoms.

• A to Z: Stye

  A stye is a red, painful bump on the eyelid caused by a backed-up oil gland.

• A to Z: Subconjunctival Hemorrhage

  A subconjunctival hemorrhage is a harmless red spot on the white of the eye.

• A to Z: Subungual Hematoma

  A subungual hematoma is blood trapped under a fingernail or toenail, often due to an injury such as a stubbed toe or a finger slammed in a door.

• A to Z: Syncope (Fainting)

  Syncope, or fainting, is a temporary loss of consciousness caused when blood flow to the brain suddenly drops, depriving the brain of oxygen.

• A to Z: Synovitis, Transient

  Transient synovitis is a temporary inflammation of a joint, most often the hip, that usually does not cause any long-term problems.

• A to Z: Tachycardia

  Learn more about types of arrhythmias and problems of the heart.

• A to Z: Testicular Torsion

  Testicular torsion is an emergency condition that happens when the spermatic cord gets twisted and cuts off blood supply, causing pain and swelling.

• A to Z: Tetanus

  Tetanus, also known as lockjaw, is a serious but preventable disease that affects the body's muscles and nerves.

• A to Z: Tetralogy of Fallot

  Learn about tetralogy of Fallot, a rare congenital heart disorder.

• A to Z: Tetraplegia

  Learn about complications of spinal cord injuries and conditions that affect the central nervous system.

• A to Z: Thrush

  Thrush (candidiasis) is an overgrowth of a type of yeast, and commonly causes infections in the mouth, vagina, and skin.

• A to Z: Thrush, Oral

  Candidiasis is an overgrowth of a type of yeast, and commonly causes infections in the mouth, vagina, and skin.

• A to Z: Thyroid Nodule

  A thyroid nodule is a lump in the thyroid gland.

• A to Z: Tic Disorder

  Learn about conditions of the brain and nervous system and conditions related to ADHD and OCD.

• A to Z: Tidal Platelet Dysgenesis

  See: Idiopathic Thrombocytopenic Purpura.

• A to Z: Tietze Disease

  Learn more about diseases of the chest wall and conditions that cause chest pain.

• A to Z: Tinea Corporis (Ringworm)

  Tinea corporis (ringworm) is a common skin infection that usually gets better with treatment.

• A to Z: Tinea Cruris (Jock Itch)

  Tinea cruris, also known as jock itch, is a skin infection of the groin area caused by several types of fungi often found on the skin.

• A to Z: Shingles

  See: Herpes Zoster.

• A to Z: Sialadenitis

  Learn about sialadenitis, an infection of the saliva-producing glands.

• A to Z: Sickle Cell Disease

  Learn about genetic disorders and diseases and conditions that affect the blood.

• A to Z: Sickle Cell Trait

  Learn about genetic disorders and diseases and conditions that affect the blood.

• A to Z: Sinus, Coccygeal or Pilonidal

  See: Pilonidal Cyst.

• A to Z: Sinusitis

  Sinusitis is an infection that causes the sinuses (moist air spaces within the bones of the face around the nose) to swell or become irritated.

• A to Z: Snake/Lizard Bites, Venomous

  A bite from a venomous (poisonous) snake or lizard is painful and also can be life threatening.

• A to Z: Spondylitis, Ankylosing

  Learn about chronic inflammatory diseases and conditions that affect the back and spine.

• A to Z: Stevens-Johnson Syndrome

  Learn about problems of the immune system and adverse reactions to drugs or infections.

• A to Z: Resonance Disorder

  In this speech problem, problems in the structure, nerves, and muscles of the mouth and throat can change the quality of the voice. Read more.

• A to Z: Retropharyngeal Abscess

  Retropharyngeal abscess is an area of infected, pus-filled tissue that forms in the deep tissues in the back of the throat.

• A to Z: Rhinitis, Allergic

  Allergic rhinitis, sometimes called "hay fever" or seasonal allergies, are allergy symptoms that occur during certain times of the year.

• A to Z: Ringworm (Dermatophytosis)

  Ringworm, or dermatophytosis, is a highly contagious infection of the skin, hair or nails caused by a type of fungus called a dermatophyte.

• A to Z: Roseola

  Roseola (also known as sixth disease) is a viral illness, most commonly affecting kids between 6 months and 2 years old.

• A to Z: Rotavirus

  Rotavirus is a highly contagious virus that can cause severe, frequent diarrhea, especially in young kids.

• A to Z Symptom: Seizure

  Seizures can be frightening, but most last only a few minutes and stop on their own.

• A to Z Symptom: Sore Throat

  A sore throat can be caused by many things, from viral and bacterial infections to seasonal allergies and gastroesophageal reflux.

• A to Z: Sanfilippo Syndrome

  Sanfilippo syndrome makes the body unable to break down certain carbohydrates (sugars) in the blood, leading to serious problems in the brain and nervous system.

• A to Z: Scabies

  Learn about parasitic infections and skin disorders.

• A to Z: Scarlet Fever

  Learn about scarlet fever,an illness with a characteristic rash that is caused by a strep infection.

• A to Z: Scrotal Pain, Acute

  A variety of things can cause pain in the scrotum (also called scrotal pain), the pouch-like structure at the base of a boy's penis.

• A to Z: Seizure, Absence

  An absence seizure (also called a petit mal seizure) is type of epileptic seizure that causes a person to briefly lose consciousness and stare ahead without moving, appearing "absent."

• A to Z: Seizure, Grand Mal

  See: Seizure, Tonic-Clonic.

• A to Z: Seizure, Petit Mal

  See: Seizure, Petit Mal.

• A to Z: Seizure, Tonic-Clonic

  A tonic-clonic seizure (also called a grand mal seizure) is a sudden attack that brings on intense muscle spasms and loss of consciousness. It is caused by abnormal brain activity and affects the entire body.

• A to Z: Septic Arthritis (Pyogenic Arthritis)

  Septic, or pyogenic, arthritis is a serious and painful infection of a joint. It's most common in children from birth to age 3 and older adults.

• A to Z: Septicemia

  Learn about this condition, in which an infection can spread into the blood and cause serious health problems.

• A to Z: Postoperative Infection

  Learn about postoperative infections, which are any kind of infections that occur following a surgical procedure.

• A to Z: Postoperative Pain

  Postoperative pain is pain or discomfort after surgery.

• A to Z: Precocious Puberty

  Learn about hormonal disorders and conditions that can affect childhood sexual development.

• A to Z: Procidentia

  Learn about conditions that affect the rectum, anus, and digestive system.

• A to Z: Pseudotumor Cerebri

  See: Hypertension, Intracranial.

• A to Z: Psychosis

  Learn about symptoms of mental illness and conditions that affect thinking and behavior.

• A to Z: Pulmonary Artery Sling

  With this condition, an artery carrying blood from the heart to the lungs can form a sling around the windpipe and block air flow. Learn more about it here.

• A to Z: Pulmonic Valvular Stenosis

  Learn about this congenital heart defect that alters blood flow through the heart and lungs and can affect a child's growth and circulation.

• A to Z: Purpura, Allergic

  See: Henoch-Schönlein Purpura (HSP).

• A to Z: Purpura, Anaphylactoid

  See: Henoch-Schönlein Purpura (HSP).

• A to Z: Purpura, Henoch-Schönlein (HSP)

  See: Henoch-Schönlein Purpura (HSP).

• A to Z: Purpura, Schönlein-Henoch

  See: Henoch-Schönlein Purpura (HSP).

• A to Z: Pyelonephritis

  Learn more about pyelonephritis and how it's treated.

• A to Z: Pyloric Stenosis

  Pyloric stenosis is a condition that happens during infancy, and affects the lower part of the stomach.

• A to Z: Pyogenic Arthritis (Septic Arthritis)

  Pyogenic, or septic, arthritis is a serious and painful infection of a joint. It's most common in children from birth to age 3 and older adults.

• A to Z: Q Fever

  Learn more about this bacterial infection that can be transmitted from animals to humans.

• A to Z: Quadriplegia

  Learn about complications of spinal cord injuries and conditions that affect the central nervous system.

• A to Z Symptom: Rash

  A rash is an area of irritated, bumpy, painful, or swollen skin. Most aren't harmful or dangerous.

• A to Z Symptom: Rectal Bleeding

  Learn about some common causes of rectal bleeding, most of which aren't serious.

• A to Z: Radial Head Subluxation

  Nursemaid's elbow is a partial dislocation of the elbow joint that happens when a ligament slips out of place near the elbow.

• A to Z: Rash, Diaper

  Diaper rash is a very common condition that can cause a baby's skin to become sore, red, and tender.

• A to Z: Rectal Prolapse

  Learn about conditions that affect the rectum, anus, and digestive system.

• A to Z: Renal Dysplasia

  Learn about potential complications of fetal development and conditions that affect the kidneys and urinary tract.

• A to Z: Paralytic Ileus

  Learn about intestinal blockages and conditions that affect the digestive tract.

• A to Z: Paresthesia

  Parathesia is a burning, prickling, itching, or tingling "pins and needles" skin sensation. Anyone who has had a foot "fall asleep" has experienced temporary paresthesia.

• A to Z: Paronychia

  Paronychia, an infection of the skin around a fingernail or toenail, usually isn't a serious problem.

• A to Z: Paroxysmal Supraventricular Tachycardia (PSVT)

  Paroxysmal supraventricular tachycardia (PSVT) is a type of arrhythmia in which the heart beats very rapidly.

• A to Z: Patent Ductus Arteriosus (PDA)

  Learn about heart conditions that affect newborn and premature babies.

• A to Z: Peptic Ulcers

  Peptic ulcers are painful sores in the lining of the stomach or upper part of the small intestine.

• A to Z: Periarteritis Nodosa

  See Polyarteritis Nodosa.

• A to Z: Pericarditis

  Learn about complications of infections and conditions that affect the heart.

• A to Z: Peritonitis

  Learn more about bacterial infections, problems of the gastrointestinal tract, and complications related to infections and diseases of the abdominal organs.

• A to Z: Peritonsillar Abscess

  A peritonsillar abscess is an area of pus-filled tissue at the back of the mouth, next to one of the tonsils.

• A to Z: Pervasive Developmental Disorder (PDD)

  Learn more about this type of autism that can impair social skills, delay speech, and cause repetitive behaviors.

• A to Z: Phenylketonuria

  In this genetic disorder, the body cannot break down the amino acid phenylalanine, which then builds up in the system and affects the brain. Learn more.

• A to Z: Phimosis

  Learn about phimosis, a condition that affects the penis and foreskin in uncircumcised males.

• A to Z: Pilonidal Cyst

  Learn more about skin infections, cysts, and abscesses.

• A to Z: Pinkeye (Conjunctivitis)

  Pinkeye (conjunctivitis) is an inflammation of the conjunctiva, the tissue covering the white part of the eye and the inner surface of the eyelid.

• A to Z: Pituitary Dwarfism

  Pituitary dwarfism is a condition in which the pituitary gland does not make enough growth hormone, resulting in a child's slow growth pattern and unusually small stature.

• A to Z: Pityriasis Rosea

  Learn about rashes and other conditions that affect the skin.

• A to Z: Pneumonia, Bacterial

  Bacterial pneumonia is a lung infection caused by bacteria (such as staph or strep).

• A to Z: Polyarteritis Nodosa

  Learn about polyarteritis nodosa (PAN), a rare disease causing inflammation of the blood vessels.

• A to Z: Polymyositis

  Polymyositis is an uncommon disease that causes muscle weakness, pain, and inflammation. It usually affects adults.

• A to Z: Open Wound, Toe

  Learn more about toe wounds and how they're treated.

• A to Z: Open Wound, Tongue

  Learn more about tongue wounds and how they're treated.

• A to Z: Open Wound, Wrist

  Learn more about wrist wounds and how they're treated.

• A to Z: Optic Nerve Glioma

  An optic nerve glioma is a type of brain tumor that forms in or around the optic nerve, which connects the eye to the brain.

• A to Z: Oral Apthae

  See Apthous Ulcers (Canker Sores).

• A to Z: Orthostatic Hypotension

  Learn about orthostatic hypotension, an abnormal drop in blood pressure that occurs when someone moves from sitting or lying down to standing up.

• A to Z: Osteodystrophy, Renal

  See: Osteodystrophy.