DEFINITION Ringworm of the scalp (tinea capitis) is a fungal infection of the scalp and hair shafts. The signs and symptoms of ringworm of the scalp may vary, but it usually appears as itchy, scaly, bald patches on the head.…
DEFINITION Ringworm of the body is a fungal infection that develops on the top layer of your skin. It’s characterized by a red circular rash with clearer skin in the middle. It may or may not itch. Ringworm gets its…
DEFINITION Hemolytic uremic syndrome (HUS) is a condition that results from the abnormal premature destruction of red blood cells. Once this process begins, the damaged red blood cells start to clog the filtering system in the kidneys, which may eventually…
DEFINITION Croup refers to an infection of the upper airway, generally in children, which obstructs breathing and causes a characteristic barking cough. The cough and other symptoms of croup are the result of inflammation around the vocal cords (larynx),…
DEFINITION Acute coronary syndrome is a term used for any condition brought on by sudden, reduced blood flow to the heart. Acute coronary syndrome symptoms may include the type of chest pressure that you feel during a heart attack, or…
DEFINITION An actinic keratosis (ak-TIN-ik ker-uh-TOE-sis) is a rough, scaly patch on your skin that develops from years of exposure to the sun. It’s most commonly found on your face, lips, ears, back of your hands, forearms, scalp or neck.…
DEFINITION Acromegaly is a hormonal disorder that develops when your pituitary gland produces too much growth hormone during adulthood. When this happens, your bones increase in size, including those of your hands, feet and face. Acromegaly usually affects middle-aged adults.…
DEFINITION Acoustic neuroma is an uncommon, noncancerous (benign) and usually slow-growing tumor that develops on the main nerve leading from your inner ear to your brain. Because branches of this nerve directly influence your balance and hearing, pressure from an…
DEFINITION Acne is a skin condition that occurs when your hair follicles become plugged with oil and dead skin cells. Acne usually appears on your face, neck, chest, back and shoulders. Effective treatments are available, but acne can be persistent.…
DEFINITION Achalasia is a rare disorder that makes it difficult for food and liquid to pass into your stomach. Achalasia occurs when the food tube (esophagus) loses the ability to squeeze food down, and the muscular valve between the esophagus…
DEFINITION Acanthosis nigricans (ak-an-THOE-sis NIE-grih-kuns) is a skin condition characterized by areas of dark, velvety discoloration in body folds and creases. The affected skin can become thickened and may smell bad. Most often, acanthosis nigricans affects your armpits, groin and…
DEFINITION Absence seizures involve brief, sudden lapses of consciousness. They’re more common in children than adults. Someone having an absence seizure may look like he or she is staring into space for a few seconds. This type of seizure usually…