Health Library

Articles In This Section

• A to Z: Hemorrhage, Intracerebral

  Learn about causes of stroke and conditions that can affect the brain.

• A to Z: Hemorrhage, Subconjunctival

  This condition happens when a blood vessel on the surface of the eye breaks open and leaves a red spot on the white of the eye. Learn more here.

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

  Learn about Henoch-Schönlein purpura, a condition in which capillaries in the skin, kidneys, and intestinal tract become inflamed and leak.

• A to Z: Hereditary Angioedema

  In this inherited condition, people can have attacks of swelling in the skin, airways, and intestines. Learn about hereditary angioedema here.

• A to Z: Fracture, Nasal (Broken Nose)

  Sports injuries or blows to the face can often cause this common type of facial injury. Learn about it here.

• A to Z: Fracture, Skull

  A skull fracture is a break or crack in one of the bones of the skull, also called the cranium.

• A to Z: Fragile X Syndrome

  Kids with this inherited disorder can do well with therapies to help treat the intellectual, emotional, and behavioral challenges they face. Learn more here.

• A to Z: Galactosemia

  Galactosemia is an inherited disorder in which the body can't break down a type of sugar called galactose.

• A to Z: Gallstones

  See: Cholelithiasis.

• A to Z: Gastritis

  Learn more about diseases and conditions of the stomach and digestive system.

• A to Z: Gastroenteritis

  Gastroenteritis is an infection that causes vomiting and diarrhea.

• A to Z: Gastroesophageal Reflux Disease (GERD)

  Learn more about diseases and conditions of the stomach and digestive system.

• A to Z: Gastroparesis

  Learn more about this problem of the stomach and digestive tract.

• A to Z: Gastroschisis

  Learn about gastroschisis, a type of hernia that some babies are born with.

• A to Z: Gestational Diabetes

  Gestational diabetes is a kind of diabetes that happens to pregnant women. Most of the time, it goes away after the mom has her baby.

• A to Z: Giardiasis

  Giardiasis is an illness of the digestive tract (stomach and intestines).

• A to Z Symptom: Fever

  A fever itself is a symptom, causes no harm, and is often the body's way of fighting infections.

• A to Z: Factor IX Deficiency (Hemophilia B)

  In factor IX deficiency (hemophilia B), the body doesn't make enough factor IX (factor 9), one of the substances the body needs to form a clot.

• A to Z: Factor VIII Deficiency (Hemophilia A)

  In factor VIII deficiency (hemophilia A), the body doesn't make enough factor VIII (factor 8), one of the substances the body needs to form a clot.

• A to Z: Febrile Seizures

  Febrile seizures are convulsions that can happen during a fever (febrile means "feverish").

• A to Z: Feeding Problems, Infant

  Some babies refuse to eat or don't eat enough. Others have problems digesting food. Learn more about common feeding problems here.

• A to Z: Fistula, Coccygeal or Pilonidal

  See: Pilonidal Cyst.

• A to Z: Flat Foot

  Flat foot is a condition in which the arches on the inside of a person's foot have less curve to them or are flat, so that the entire sole of the foot rests on the ground when the person is standing.

• A to Z: Flatulence, Eructation, and Gas Pain

  It may seem embarrassing to talk about, but intestinal gas and the sounds and smells it causes are common and usually totally normal. Learn more here.

• A to Z: Flu (Influenza)

  Learn more about influenza, a highly contagious viral infection of the respiratory tract.

• A to Z: Food Poisoning

  Food poisoning happens when bacteria (and, sometimes, viruses or other germs) get into food or drinks.

• A to Z: Foreign Body, Ear

  Having a foreign object in the ear is a common cause for a visit to the emergency room, especially for kids under age 6.

• A to Z: Foreign Body, Eye

  To prevent damage to the eye, any object that isn't washed out right away by tears must be removed.

• A to Z: Foreign Body, Nose

  Having an object (or foreign body) in the nose is a common cause for a visit to the emergency room, especially for kids under age 6.

• A to Z: Ectopic Ureter

  The kidneys and urinary tract (which includes the ureters) filter and eliminate wastes from the blood. But sometimes a ureter doesn't connect to the bladder in the usual place, a condition known as an ectopic ureter.

• A to Z: Eczema

  Learn about genetic conditions, allergic reactions, and conditions that can affect the skin.

• A to Z: Eczema Herpeticum

  Eczema herpeticum is a skin infection that occurs when the skin becomes infected by herpes simplex (the type of viruses that causes cold sores).

• A to Z: Edema

  Learn about edema, swelling due to the build-up of excess fluid in body tissues.

• A to Z: Encephalopathy

  Learn about encephalopathy, a broad term used to describe brain dysfunction.

• A to Z: Encopresis

  Encopresis (soiling) is a condition that causes a child beyond the age of toilet training to have bowel movements (poop) in his or her underwear.

• A to Z: Endocardial Cushion Defect

  Learn about congenital heart defects and conditions that affect newborn babies.

• A to Z: Endometritis

  Learn about complications of infections and conditions that affect the female reproductive system.

• A to Z: Enlarged Tonsils

  See: Hypertrophy, Tonsillar.

• A to Z: Enteritis

  Learn more about this common complication of infections and conditions that can affect the small intestine and digestive system.

• A to Z: Enterovirus

  Enterovirus infections can affect the digestive tract, skin, and respiratory and central nervous systems.

• A to Z: Enuresis

  Enuresis (bedwetting) is a condition where a person has trouble controlling his or her urination (pee).

• A to Z: Eosinophilic Esophagitis

  Learn about allergic reactions and diseases of the esophagus and gastrointestinal tract.

• A to Z: Epididymitis

  Epididymitis refers to swelling and inflammation of the epididymis, the coiled tube at the back of the testicle that holds and carries sperm.

• A to Z: Epilepsy

  Epilepsy is a seizure disorder in which electrical signals in the brain misfire, causing temporary communication problems between nerve cells. Someone who gets recurrent seizures is thought to have epilepsy.

• A to Z: Epistaxis (Nosebleed)

  Epistaxis is another word for nosebleed, when small blood vessels break in the tissue lining of the nose.

• A to Z: Erythema Multiforme

  Erythema multiforme is a skin condition caused by a hypersensitive reaction to an infection or, in some cases, medication.

• A to Z: Esophagitis

  Learn about conditions that affect the esophagus and upper gastrointestinal tract.

• A to Z: Expressive Language Disorder

  This type of speech problem can make it hard for kids to put words together and express what they want to say. Learn more here.

• A to Z Symptom: Fainting

  In most cases, fainting is not a sign of a dangerous problem, but should still be discussed with a doctor.

• A to Z: Diabetes, Type 1

  Diabetes is a disease that affects how the body uses glucose. In type 1 diabetes, the pancreas doesn't make enough insulin, a chemical in the body that helps glucose enter the cells.

• A to Z: Diabetic Ketoacidosis

  Diabetic ketoacidosis (DKA) can be a life-threatening complication of uncontrolled diabetes.

• A to Z: Diplegia

  Learn about conditions that affect the brain, central nervous system, and muscle coordination.

• A to Z: Down Syndrome

  Learn about Down syndrome (DS), a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically.

• A to Z: Drug Withdrawal, Newborn

  Newborn babies who were exposed to drugs or alcohol while in the womb can develop this syndrome after birth. Learn about it here.

• A to Z: Duodenitis

  Learn more about diseases and conditions of the stomach and digestive system.

• A to Z: Dysmenorrhea

  "Dysmenorrhea" means difficult or painful periods.

• A to Z: Dysphagia

  Swallowing difficulties can affect many aspects of a child's health, including feeding, breathing, and overall growth.

• A to Z: Dysrhythmia

  Learn more about dysrhythmia: an abnormality in the heart's beat or rhythm caused by electrical impulses functioning improperly.

• A to Z: Dysuria

  Learn more about dysuria (or painful urination) and its treatment.

• Definition: DNA

  DNA is the genetic information inside the cells of the body that helps make people who they are.

• A to Z: Eardrum, Perforated

  A perforated (or ruptured) eardrum is a hole in the eardrum caused by injury or infection.

• A to Z: Eating Disorder

  Eating disorders involve self-critical, negative thoughts and feelings about body weight and food, and eating habits that disrupt normal body function and daily activities.

• A to Z: Ebstein’s Anomaly

  Learn about Ebstein's anomaly, a rare defect in the right side of the heart that is present at birth (congenital).

• A to Z: Cytomegalovirus

  Learn about viral infections and conditions that can affect pregnancy, newborn babies, and people with weakened immune systems.

• A to Z: Chronic Lymphocytic Thyroiditis

  See: Hashimoto's Thyroiditis.

• Definition: Cough

  Cough is a common symptom in people who have asthma, although it can occur for many other reasons.

• A to Z Symptom: Diarrhea

  Diarrhea (loose, watery, or more frequent stools) can be a symptom of many conditions, including common infections. Most cases go away in a few days with proper home care.

• A to Z Symptom: Dizziness

  Dizziness refers to feelings of lightheadedness, imbalance, or vertigo (the sensation that one’s surroundings are spinning or moving).

• A to Z: Deformity, Acquired

  Learn about complications of injuries and illnesses and conditions that affect the size and shape of body parts.

• A to Z: Deformity, Congenital

  Learn about types of birth defects and conditions that affect the size and shape of body parts.

• A to Z: Dehydration

  Learn about dehydration, a condition that occurs when someone loses more fluids than he or she takes in.

• A to Z: Dental Cavities

  A dental cavity is a hole in the tooth that can grow bigger and deeper over time.

• A to Z: Dermatitis

  Learn about dermatitis, inflammation of the skin that causes itching and discomfort.

• A to Z: Dermatitis, Atopic

  Learn about atopic dermatitis, an inflammation of the skin that causes itching and discomfort.

• A to Z: Dermatitis, Contact

  Learn about contact dermatitis, inflammation of the skin that causes itching and discomfort.

• A to Z: Dermatitis, Infantile Seborrheic

  Learn about dermatitis, inflammation of the skin that causes itching and discomfort.

• A to Z: Dermatitis, Seborrheic

  Learn about seborrheic dermatitis, inflammation of the skin that causes itching and discomfort.

• A to Z: Dermatomyositis

  Learn about dermatomyositis, an inflammatory muscle disease that weakens muscles and produces a distinctive skin rash.

• A to Z: Dermatophytosis (Ringworm)

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

• A to Z: Developmental Delay

  As kids grow they develop socially and emotionally, and they learn speech, language, motor skills, and cognitive thinking. But in some kids that development can be delayed. Learn more here.

• A to Z: Diabetes

  Diabetes is a disease that affects the way the body handles glucose, a sugar released by the foods we eat.

• A to Z: Diabetes Insipidus, Central

  In central diabetes insipidus, the kidneys make large amounts of urine, causing the body to lose too much water.

• A to Z: Diabetes Insipidus, Nephrogenic

  In nephrogenic diabetes insipidus, the body loses too much water because of a problem with the kidneys.

• A to Z: Contusion (Bruise), Buttocks

  Learn more about contusions (bruises) of the buttocks.

• A to Z: Contusion (Bruise), Chest

  Learn more about contusions (bruises) of the chest.

• A to Z: Contusion (Bruise), Elbow

  Learn more about elbow contusions (bruises).

• A to Z: Contusion (Bruise), Eye

  Learn more about black eyes and contusions (bruises) of the eye.

• A to Z: Contusion (Bruise), Eyelid

  Learn more about black eyes and eyelid contusions in children.

• A to Z: Contusion (Bruise), Face, Scalp, & Neck

  Learn about contusions (bruises) of the face, scalp, and neck.

• A to Z: Contusion (Bruise), Finger

  Learn more about contusions (bruises) of the finger.

• A to Z: Contusion (Bruise), Forearm

  Learn more about contusions (bruises) of the forearm.

• A to Z: Contusion (Bruise), Hand

  Learn more about contusions (bruises) of the hand.

• A to Z: Contusion (Bruise), Hip

  Learn more about contusions (bruises) of the hip.

• A to Z: Contusion (Bruise), Knee

  Learn more about contusions (bruises) of the knee.

• A to Z: Contusion (Bruise), Lower Leg

  Learn more about contusions (bruises) of the lower leg.

• A to Z: Contusion (Bruise), Shoulder

  Learn more about contusions (bruises) of the shoulder.

• A to Z: Coronavirus

  This common viral infection can affect the respiratory tract. Almost everyone has had it at some point in their life. Learn about coronavirus here.

• A to Z: Costochondritis

  Costochondritis is an inflammation of the cartilage that attaches a rib to the breastbone (sternum).

• A to Z: Coxa Valga

  A to Z: Coxa Valga

• A to Z: Coxsackievirus

  Learn about coxsackieviruses, part of the enterovirus family of viruses that live in the human digestive tract.

• A to Z: Craniopharyngioma

  Learn about craniopharyngioma, a treatable type of brain tumor that can affect a person's vision, growth, and development.

• A to Z: Crohn’s Disease

  Crohn's disease causes problems in the intestine (bowel) that can prevent the bowel from digesting food well.

• A to Z: Croup

  Croup is a viral infection that causes an inflammation of the upper airways — the voice box (larynx) and windpipe (trachea).

• A to Z: Cryptorchidism

  Cryptorchidism 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: Cyst, Cerebral

  A cerebral cyst is a sac filled with fluid, and sometimes other materials, that develops in or around the brain.

• A to Z: Cyst, Meibomian

  A meibomian cyst, or chalazion, is a lump on the inner side of the eyelid. It occurs when one of the small oil glands becomes blocked.

• A to Z: Cyst, Ovarian

  Learn about complications of ovulation and conditions that affect the female reproductive system.

• A to Z: Cystitis

  Learn about cystitis (inflammation of the bladder, commonly called a bladder infection). It is the most common type of urinary tract infection (UTI).

• A to Z: Chalazion

  A chalazion is a lump on the inner side of the eyelid. It occurs when one of the small oil glands becomes blocked.

• A to Z: Charcot-Marie-Tooth Disease

  Learn about neurological disorders and conditions that affect the arms and legs.

• A to Z: Cholangitis

  Learn more about infections and problems of the liver and biliary tract.

• A to Z: Cholelithiasis (Gallstones)

  Learn about cholelithiasis, the presence of gallstones (hard, pebble-like objects made of bile).

• A to Z: Chondrodystrophy

  Learn about genetic disorders and conditions that affect growth and development.

• A to Z: Cleft Lip, Bilateral

  Learn about bilateral cleft lip, a common birth defect in which a baby's lip doesn't form properly, resulting in splits (clefts) on both sides of the lip.

• A to Z: Cleft Lip, Unilateral

  Learn about unilateral cleft lip, a common birth defect in which a baby's lip doesn't form properly, resulting in a split (cleft) on one side of the lip.

• A to Z: Cleft Palate With Cleft Lip, Bilateral

  A cleft palate with a bilateral cleft lip is a common birth defect in which a baby's lip and palate (roof of mouth) don't form properly. As a result there is a split or opening (cleft) on both sides of the lip that can extend all the way from the nose to the back of the palate.

• A to Z: Cleft Palate With Cleft Lip, Unilateral

  A cleft palate with a unilateral cleft lip is a common birth defect in which a baby's lip and palate (roof of mouth) don't form properly. As a result there is a split or opening (cleft) on one side of the lip that can extend all the way from the nose to the back of the palate.

• A to Z: Coarctation of the Aorta (COA)

  Learn about coarctation of the aorta, a treatable congenital heart defect in which a person's aorta is narrowed at some point.

• A to Z: Colitis

  Learn about inflammatory disorders and conditions that affect the intestines and digestive system.

• A to Z: Common Variable Immunodeficiency (CVID)

  Learn about this common disorder that lowers the amount of antibodies a person's body can make and limits the ability to fight infections.

• A to Z: Complete Transposition of the Great Vessels

  In this condition that starts in the womb, reversed connections of the aorta and pulmonary artery prevent the blood from getting oxygen. Learn more here.

• A to Z: Compression of the Brain

  It is important to carefully monitor and treat this potential complication of head injuries and diseases affecting the brain. Read about it here.

• A to Z: Concussion

  A concussion is a brain injury that causes temporary changes in the way the brain works. It's usually a result of impact or a blow to the head.

• A to Z: Congenital Anomaly

  Sometimes babies are born with anomalies - one or more parts of the body that are different from normal in size, shape, or functioning. Learn more here.

• A to Z: Congestive Heart Failure

  In this condition, which can affect a child's breathing, activity, and growth, the heart is unable to pump blood efficiently and meet the needs of the body.

• A to Z: 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: Constipation

  Constipation -- having fewer and harder bowel movements (poops) than usual -- is rarely due to a serious condition.

• A to Z: Contusion (Bruise), Abdomen

  Learn more about contusions (bruises) of the abdomen.

• A to Z: Contusion (Bruise), Ankle

  Learn more about ankle contusions (bruises).

• A to Z: Contusion (Bruise), Back

  Learn more about contusions (bruises) of the back.

• A to Z: Bronchiolitis

  Bronchiolitis is a common illness of the respiratory tract caused by an infection that affects the bronchioles, tiny airways that lead to the lungs.

• A to Z: Bronchitis

  Bronchitis (say: bron-kye-tis) is an inflammation of the lining of the bronchial tubes, the airways that connect the trachea (windpipe) to the lungs.

• A to Z: Bruxism

  Bruxism is the medical term for grinding the teeth or clenching the jaws.

• A to Z: Bulimia

  Learn about eating disorders and complications of negative thoughts about eating, food, and body image.

• A to Z: Burn, First-Degree

  A first-degree burn is a minor burn that only affects the top layer of skin, or epidermis. It is the mildest of the three types of burns (first-degree, second-degree, and third-degree).

• A to Z: Burn, Second-Degree

  A second-degree burn affects the top two layers of skin (the epidermis and dermis). It is more serious than a first-degree burn.

• A to Z: Burn, Third-Degree

  Third-degree burns, or full-thickness burns, are the most serious type of burn. They involve all the layers of the skin and underlying tissue and can cause permanent damage.

• A to Z Symptom: Chest Pain

  Most causes of chest pain in kids and teens are not serious and will clear up with minimal or no treatment.

• A to Z Symptom: Cough

  Coughing is a symptom, not a disease, and sometimes can help clear the airway.

• A to Z Symptom: Crying in Babies

  Babies use crying to communicate, and during the first 3 months of life, they cry a lot. Knowing what to expect can help parents and caregivers manage.

• A to Z: Candidiasis

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

• A to Z: Canker Sores

  See Apthous Ulcers (Canker Sores).

• A to Z: Cardiac Arrest

  With this medical emergency, the heart suddenly stops beating and prevents oxygen from getting to the body. Read more about it here.

• A to Z: Cardiomegaly

  Diseases can put added strain on the heart. As it enlarges to pump more blood to the body, the heart muscle weakens and does not work well in this condition. Read more here.

• A to Z: Cardiomyopathy

  Learn about cardiomyopathy, a disease in which the heart muscle becomes weak and enlarged, making it difficult to pump blood through the body.

• A to Z: Cellulitis

  Learn more about cellulitis, an infection of the skin and underlying tissues.

• A to Z: Cellulitis, Orbital

  Learn about orbital cellulitis, a dangerous infection affecting the eye and its surrounding tissue and skin.

• A to Z: Central Line Infection

  A central line — a tube surgically placed into a blood vessel — can be a convenient way to receive medicine through a vein over a long period of time, but it carries the risk of infection.

• A to Z: Central Sleep Apnea

  Learn more about this condition, in which abnormal brain signals cause a person's breathing to stop and start repeatedly during sleep.

• A to Z: Cerebellar Ataxia

  Learn about cerebellar ataxia, the loss of muscle coordination caused by disease or injury to the cerebellum.