Penicillin allergy

Penicillin allergy is an overreaction by your immune system to penicillin and related antibiotics. If you have a penicillin allergy, your reaction to taking the antibiotic may range from a rash to anaphylaxis, a potentially life-threatening condition.

Penicillin antibiotics are widely prescribed for bacterial infections, such as strep throat. However, not all unfavorable reactions to penicillin are a true penicillin allergy.

It isn't clear why some people develop penicillin allergy. Once you've had an allergic reaction to penicillin, the simplest way to prevent penicillin allergy is to avoid penicillin and related antibiotics.

Peanut allergy

Peanut allergy is common, especially in children. Peanut allergy symptoms can range from a minor irritation to a life-threatening reaction (anaphylaxis). For some people with peanut allergy, even tiny amounts of peanuts can cause a serious reaction.

If you or your child has had a reaction to peanuts, tell your doctor about it. Peanut allergy is one of the most common causes of severe allergy attacks.

It's important to get even a minor reaction to peanuts checked out. Even if you or your child has had only a mild allergic reaction in the past, there's still a risk of a more serious future reaction.

Nickel allergy

Nickel allergy is one of the most common causes of allergic contact dermatitis — an itchy rash that appears when your skin touches a usually harmless substance.

Nickel allergy is commonly associated with earrings and other jewelry, particularly jewelry associated with body piercings. But nickel can be found in many everyday items — from coins to zippers, from cellphones to eyeglass frames.

Nickel allergy can affect people of all ages. A nickel allergy usually develops after repeated or prolonged exposure to items containing nickel. Treatments can reduce the symptoms of nickel allergy. Once you develop nickel allergy, however, you will always be sensitive to the metal and need to avoid contact.

Nickel allergy

Nickel allergy is one of the most common causes of allergic contact dermatitis — an itchy rash that appears when your skin touches a usually harmless substance.

Nickel allergy is commonly associated with earrings and other jewelry, particularly jewelry associated with body piercings. But nickel can be found in many everyday items — from coins to zippers, from cellphones to eyeglass frames.

Nickel allergy can affect people of all ages. A nickel allergy usually develops after repeated or prolonged exposure to items containing nickel. Treatments can reduce the symptoms of nickel allergy. Once you develop nickel allergy, however, you will always be sensitive to the metal and need to avoid contact.

Mold allergy

If you have a mold allergy, your immune system overreacts when you breathe in mold spores. This triggers a cascade of reactions that lead to allergic symptoms. Like other allergies, a mold allergy can make you cough, make your eyes itch and cause other symptoms that make you miserable. In some people, mold allergy is linked to asthma and exposure causes restricted breathing and other airway symptoms.

If you have a mold allergy, the best defense is to reduce your exposure to the types of mold that cause your reaction. While it isn't always possible to avoid mold allergy triggers, medications can help keep mold allergy reactions under control.

Milk allergy

Milk allergy is an abnormal response by the body's immune system to milk and products containing milk. Cow's milk is the usual cause of milk allergy, but milk from sheep, goats and buffalo also can cause a reaction. Some children who are allergic to cow's milk are allergic to soy milk, too. Milk allergy is one of the most common food allergies in children.

A milk allergy usually occurs minutes to hours after consuming milk. Signs and symptoms of milk allergy range from mild to severe and can include wheezing, vomiting, hives and digestive problems. Rarely, milk allergy can cause anaphylaxis — a severe, life-threatening reaction.

Avoidance is the primary treatment for milk allergy. Fortunately, most children outgrow a milk allergy by age 3.

Latex allergy

Latex allergy is a reaction to certain proteins found in natural rubber latex, a product manufactured from a milky fluid that comes from the rubber tree. If you have a latex allergy, your body mistakes latex for a harmful substance.

Latex allergy may cause allergic reactions ranging from sneezing or a runny nose to anaphylaxis, a potentially life-threatening condition. Your doctor may determine if you have a latex allergy or if you're at risk of developing a latex allergy.

Understanding latex allergy and becoming familiar with common sources of latex can help you prevent your own allergic reactions or those of someone else.

Food allergy

Food allergy is an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives or swollen airways. In some people, a food allergy can cause severe symptoms or even a life-threatening reaction known as anaphylaxis.

Food allergy affects an estimated 6 to 8 percent of children under age 5, and about 3 to 4 percent of adults. While there's no cure, some children outgrow their food allergy as they get older. It's easy to confuse a food allergy with a much more common reaction known as food intolerance. While bothersome, food intolerance is a less serious condition that does not involve the immune system.

Egg allergy

Eggs are one of the most common allergy-causing foods in children.

Egg allergy symptoms usually occur a few minutes to a few hours after eating eggs or foods containing eggs. Signs and symptoms range from mild to severe and can include skin rashes, hives, nasal inflammation, and vomiting or other digestive problems. Rarely, egg allergy can cause anaphylaxis — a life-threatening reaction.

Egg allergy can occur as early as infancy. Most children outgrow their egg allergy before adolescence. But in some cases, it continues into adulthood.

Dust mite allergy

Dust mite allergy is an allergic reaction to tiny bugs that commonly live in house dust. Signs of dust mite allergy include those common to hay fever, such as sneezing and runny nose. Many people with dust mite allergy also experience signs of asthma, such as wheezing and difficulty breathing.

Dust mites, relatives of the spider, are too small to see without a microscope. Dust mites eat skin cells shed by people, and they thrive in warm, humid environments. In most homes, bedding, upholstered furniture and carpeting provide an ideal environment for dust mites.

Steps to reduce the number of dust mites in your home can often control dust mite allergy. Medications or other treatments may be necessary to relieve symptoms and manage asthma.

Allergies

Allergies occur when your immune system reacts to a foreign substance such as pollen, bee venom or pet dander.

Your immune system produces substances known as antibodies. Some of these antibodies protect you from unwanted invaders that could make you sick or cause an infection. When you have allergies, your immune system makes antibodies that identify a particular allergen as something harmful, even though it isn't. When you come into contact with the allergen, your immune system's reaction can inflame your skin, sinuses, airways or digestive system.

The severity of allergies varies from person to person and can range from minor irritation to anaphylaxis — a potentially life-threatening emergency. While most allergies can't be cured, a number of treatments can help relieve your allergy symptoms.

Primary aldosteronism

Primary aldosteronism (al-DOS-tuh-ro-niz-um) is a type of hormonal disorder that leads to high blood pressure. Your adrenal glands produce a number of essential hormones. One of these is aldosterone, which balances sodium and potassium in your blood. In primary aldosteronism, your adrenal glands produce too much aldosterone, causing you to lose potassium and retain sodium. The excess sodium in turn holds onto water, increasing your blood volume and blood pressure.

Diagnosis and treatment of primary aldosteronism are important because people with this form of high blood pressure have a higher risk of heart disease and stroke. Also, the high blood pressure associated with primary aldosteronism may be curable. Options for people with primary aldosteronism include medications, lifestyle modifications and surgery.

Airplane ear

Airplane ear is the stress exerted on your eardrum and other middle ear tissues when the air pressure in your middle ear and the air pressure in the environment are out of balance. You may experience airplane ear at the beginning of a flight when the airplane is climbing or at the end of a flight when the airplane is descending. These fast changes in altitude cause air pressure changes and can trigger airplane ear.

Airplane ear is also called ear barotrauma, barotitis media or aerotitis media.

Usually self-care steps — such as yawning, swallowing or chewing gum — can prevent or correct the differences in air pressure and improve airplane ear symptoms. However, a severe case of airplane ear may need to be treated by a doctor.

Age spots (liver spots)

Age spots — also called liver spots and solar lentigines — are flat gray, brown or black spots. They vary in size and usually appear on the face, hands, shoulders and arms — areas most exposed to the sun. Though age spots are very common in adults older than age 40, they can affect younger people as well.

True age spots are harmless and don't need treatment, but they can look like cancerous growths. For cosmetic reasons, age spots can be lightened with skin-bleaching products or removed. However, preventing age spots — by avoiding the sun and using sunscreen — may be the easiest way to maintain your skin's youthful appearance and to avoid these dark skin spots.

Attention-deficit/hyperactivity disorder (ADHD) in children

Attention-deficit/hyperactivity disorder (ADHD) is a chronic condition that affects millions of children and often persists into adulthood. ADHD includes a combination of problems, such as difficulty sustaining attention, hyperactivity and impulsive behavior.

Children with ADHD also may struggle with low self-esteem, troubled relationships and poor performance in school. Symptoms sometimes lessen with age. However, some people never completely outgrow their ADHD symptoms. But they can learn strategies to be successful.

While treatment won't cure ADHD, it can help a great deal with symptoms. Treatment typically involves medications and behavioral interventions. Early diagnosis and treatment can make a big difference in outcome.

Mesenteric lymphadenitis

Lymphadenitis is a condition in which your lymph nodes — tissues that help your body fight off illness — become inflamed. Mesenteric lymphadenitis (mez-un-TER-ik lim-fad-uh-NIE-tis) is an inflammation of the lymph nodes in the membrane that attaches your intestine, or bowel, to your abdominal wall (mesentery). Mesenteric lymphadenitis usually results from an intestinal infection.

There are about 26 feet of bowel in your abdominal cavity. The bowel is the only organ in your body that "is free to move about its cavity," but the mesentery limits that movement. If not for the mesentery, the bowel likely would twist upon itself, causing obstruction.

Mesenteric lymphadenitis occurs mainly in children and teens and often mimics the signs and symptoms of appendicitis. Unlike appendicitis, however, mesenteric lymphadenitis is seldom serious and clears on its own

Addison's disease

Addison's disease is a disorder that occurs when your body produces insufficient amounts of certain hormones produced by your adrenal glands. In Addison's disease, your adrenal glands produce too little cortisol and often insufficient levels of aldosterone as well.

Also called adrenal insufficiency, Addison's disease occurs in all age groups and affects both sexes. Addison's disease can be life-threatening.

Treatment for Addison's disease involves taking hormones to replace the insufficient amounts being made by your adrenal glands, in order to mimic the beneficial effects produced by your naturally made hormones.

Nicotine dependence

Nicotine dependence is an addiction to tobacco products caused by the drug nicotine. Nicotine dependence — also referred to as tobacco dependence — means you can't stop using the substance, even though it's causing you harm. While it's the nicotine in tobacco that causes nicotine dependence, the toxic effects come mainly from other substances in tobacco. Smokers have much higher rates of heart disease, stroke and cancer than do nonsmokers.

Nicotine produces physical and mood-altering effects in your brain that are temporarily pleasing. These effects make you want to use tobacco and lead to dependence. At the same time, stopping tobacco use causes withdrawal symptoms, including irritability and anxiety.

Many effective treatments for nicotine dependence are available to help you manage withdrawal and stop smoking for good. Ask your doctor for help.

Compulsive gambling

Compulsive gambling is the uncontrollable urge to keep gambling despite the toll it takes on your life. If you're prone to compulsive gambling, you may continually chase bets, lie or hide your behavior, and resort to theft or fraud to support your addiction.

Compulsive gambling is a serious condition that can destroy lives. Although treating compulsive gambling can be challenging, many compulsive gamblers have found help through professional treatment.

Drug addiction

Drug addiction is a dependence on an illegal drug or a medication. When you're addicted, you may not be able to control your drug use and you may continue using the drug despite the harm it causes. Drug addiction can cause an intense craving for the drug. You may want to quit, but most people find they can't do it on their own.

For many people, what starts as casual use leads to drug addiction. Drug addiction can cause serious, long-term consequences, including problems with physical and mental health, relationships, employment and the law.

You may need help from your doctor, family, friends, support groups or an organized treatment program to overcome your drug addiction and stay drug-free.

Alcoholism

Alcoholism is a chronic and often progressive disease that includes problems controlling your drinking, being preoccupied with alcohol, continuing to use alcohol even when it causes problems, having to drink more to get the same effect (physical dependence), or having withdrawal symptoms when you rapidly decrease or stop drinking. If you have alcoholism, you can't consistently predict how much you'll drink, how long you'll drink, or what consequences will occur from your drinking.

It's possible to have a problem with alcohol, even when it has not progressed to the point of alcoholism. Problem drinking means you drink too much at times, causing repeated problems in your life, although you're not completely dependent on alcohol.

Binge drinking — a pattern of drinking where a male consumes five or more drinks in a row, or a female downs at least four drinks in a row — can lead to the same health risks and social problems associated with alcoholism. The more you drink, the greater the risks. Binge drinking, which often occurs with teenagers and young adults, may lead to faster development of alcoholism.

If you have alcoholism or you have a problem with alcohol, you may not be able to cut back or quit without help. Denying that you have a problem is usually part of alcoholism and other types of excessive drinking.

Acute sinusitis

Acute sinusitis (acute rhinosinusitis) causes the cavities around your nasal passages (sinuses) to become inflamed and swollen. This interferes with drainage and causes mucus to build up.

With acute sinusitis, it may be difficult to breathe through your nose. The area around your eyes and face may feel swollen, and you may have throbbing facial pain or a headache.

Acute sinusitis is most often caused by the common cold. Other triggers include bacteria, allergies and fungal infections. Treatment of acute sinusitis depends on the cause. In most cases, home remedies are all that's needed. However, persistent sinusitis can lead to serious infections and other complications. Sinusitis that lasts more than 12 weeks, or keeps coming back, is called chronic sinusitis.

Acute lymphocytic leukemia

Acute lymphocytic leukemia (ALL) is a type of cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made.

The word "acute" in acute lymphocytic leukemia comes from the fact that the disease progresses rapidly and creates immature blood cells, rather than mature ones. The "lymphocytic" in acute lymphocytic leukemia refers to the white blood cells called lymphocytes, which ALL affects. Acute lymphocytic leukemia is also known as acute lymphoblastic leukemia.

Acute lymphocytic leukemia is the most common type of cancer in children, and treatments result in a good chance for a cure. Acute lymphocytic leukemia can also occur in adults, though the chance of a cure is greatly reduced.

Acute liver failure

Acute liver failure occurs when your liver rapidly loses its ability to function. More commonly, liver failure develops slowly over the course of years. But in acute liver failure, liver failure develops in a matter of days.

Acute liver failure can cause many complications, including excessive bleeding and increasing pressure in the brain. Another term for acute liver failure is fulminant hepatic failure.

Acute liver failure is a medical emergency that requires hospitalization. Some causes of acute liver failure can be reversed with treatment. But in other situations, a liver transplant may be the only cure for acute liver failure.

Acute kidney failure

Acute kidney failure occurs when your kidneys suddenly become unable to filter waste products from your blood. When your kidneys lose their filtering ability, dangerous levels of wastes may accumulate and your blood's chemical makeup may get out of balance.

Acute kidney failure — also called acute renal failure or acute kidney injury — develops rapidly over a few hours or a few days. Acute kidney failure is most common in people who are already hospitalized, particularly in critically ill people who need intensive care.

Acute kidney failure can be fatal and requires intensive treatment. However, acute kidney failure may be reversible. If you're otherwise in good health, you may recover normal kidney function.

Acute kidney failure

Acute kidney failure occurs when your kidneys suddenly become unable to filter waste products from your blood. When your kidneys lose their filtering ability, dangerous levels of wastes may accumulate and your blood's chemical makeup may get out of balance.

Acute kidney failure — also called acute renal failure or acute kidney injury — develops rapidly over a few hours or a few days. Acute kidney failure is most common in people who are already hospitalized, particularly in critically ill people who need intensive care.

Acute kidney failure can be fatal and requires intensive treatment. However, acute kidney failure may be reversible. If you're otherwise in good health, you may recover normal kidney function.

Acute kidney failure

Acute kidney failure occurs when your kidneys suddenly become unable to filter waste products from your blood. When your kidneys lose their filtering ability, dangerous levels of wastes may accumulate and your blood's chemical makeup may get out of balance.

Acute kidney failure — also called acute renal failure or acute kidney injury — develops rapidly over a few hours or a few days. Acute kidney failure is most common in people who are already hospitalized, particularly in critically ill people who need intensive care.

Acute kidney failure can be fatal and requires intensive treatment. However, acute kidney failure may be reversible. If you're otherwise in good health, you may recover normal kidney function.

Acute coronary syndrome

Acute coronary syndrome is a term used for any condition brought on by sudden, reduced blood flow to the heart. Acute coronary syndrome can describe chest pain you feel during a heart attack, or chest pain you feel while you're at rest or doing light physical activity (unstable angina). Acute coronary syndrome is often diagnosed in an emergency room or hospital.

Acute coronary syndrome is treatable if diagnosed quickly. Acute coronary syndrome treatments vary, depending on your signs, symptoms and overall health condition.

Actinic keratosis

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 — areas of skin typically exposed to the sun.

An actinic keratosis, also known as solar keratosis, enlarges slowly and usually causes no signs or symptoms other than a patch or small spot on your skin. An actinic keratosis takes years to develop, usually first appearing in older adults. Many doctors consider an actinic keratosis to be precancerous because it can develop into skin cancer.

You can reduce your risk of actinic keratosis by minimizing your sun exposure and protecting your skin from ultraviolet (UV) rays.

Acromegaly

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.

In children who are still growing, too much growth hormone can cause a condition called gigantism. These children have exaggerated bone growth and an abnormal increase in height.

Because acromegaly is uncommon and physical changes occur gradually, the condition often isn't recognized immediately; sometimes not for years. If not treated promptly, acromegaly can lead to serious illness and even become life-threatening. However, available treatments for acromegaly can reduce your risk of complications and significantly improve your symptoms, including the enlargement of your features.

HIV/AIDS

AIDS is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight the organisms that cause disease.

HIV is a sexually transmitted infection. It can also be spread by contact with infected blood, or from mother to child during pregnancy, childbirth or breast-feeding. It can take years before HIV weakens your immune system to the point that you have AIDS.

There's no cure for HIV/AIDS, but there are medications that can dramatically slow the progression of the disease. These drugs have reduced AIDS deaths in many developed nations. But HIV continues to decimate populations in Africa, Haiti and parts of Asia.

Acoustic neuroma

Acoustic neuroma is a 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 acoustic neuroma can cause hearing loss, ringing in your ear and unsteadiness.

Also known as vestibular schwannoma, acoustic neuroma is an uncommon cause of hearing loss. Acoustic neuroma usually grows slowly or not at all, but in a few cases it may grow rapidly and become large enough to press against the brain and interfere with vital functions.

Treatments for acoustic neuroma include regular monitoring, radiation and surgical removal.

Acne

Acne is a skin condition that occurs when your hair follicles become plugged with oil and dead skin cells. Acne most commonly appears on your face, neck, chest, back and shoulders. Acne can be distressing and annoyingly persistent. Acne lesions heal slowly, and when one begins to resolve, others seem to crop up.

Depending on its severity, acne can cause emotional distress and lead to scarring of the skin. The good news is that effective treatments are available — and the earlier treatment is started, the lower your risk of lasting physical and emotional damage.

ACL injury

An ACL injury is the tearing of the anterior cruciate (KROO-she-ate) ligament, or ACL, inside your knee joint. An ACL injury most commonly occurs during sports that involve sudden stops and changes in direction — such as basketball, soccer, tennis and volleyball.

Immediately after an ACL injury, your knee may swell, feel unstable and become too painful to bear weight. Many people hear or feel a "pop" in their knee when an ACL injury occurs.

Depending on the severity of your ACL injury, treatment may include surgery to replace the torn ligament followed by rehabilitation exercises to help you regain strength and stability. If your favorite sport involves pivoting or jumping, a proper training program may help reduce your chances of an ACL injury.

Achilles tendon rupture

Achilles (uh-KILL-eez) tendon rupture is an injury that affects the back of your lower leg. It most commonly occurs in people playing recreational sports.

The Achilles tendon is a strong fibrous cord that connects the muscles in the back of your calf to your heel bone. If you overstretch your Achilles tendon, it can tear (rupture). The tendon can rupture completely or just partially.

If you have an Achilles tendon rupture, you might feel a pop or snap, followed by an immediate sharp pain in the back of your ankle and lower leg that usually affects your ability to walk properly. Surgery is often the best treatment option to repair an Achilles tendon rupture. For many people, however, nonsurgical treatment works just as well.

Achilles tendinitis

Achilles tendinitis is an overuse injury of the Achilles (uh-KIL-eez) tendon, the band of tissue that connects calf muscles at the back of the lower leg to your heel bone.

Achilles tendinitis most commonly occurs in runners who have suddenly increased the intensity or duration of their runs. It's also common in middle-aged people who play sports, such as tennis or basketball, only on the weekends.

Most cases of Achilles tendinitis can be treated with relatively simple, at-home care under your doctor's supervision. Self-care strategies are usually necessary to prevent recurring episodes. More-serious cases of Achilles tendinitis can lead to tendon tears (ruptures) that may require surgical repair.

Acanthosis nigricans

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 neck.

These skin changes typically occur in people who are obese or have diabetes. Children who develop the condition are at higher risk of developing type 2 diabetes. More rarely, acanthosis nigricans can be a warning sign of a cancerous tumor in an internal organ, such as the stomach or liver.

Acanthosis nigricans is most common in Native Americans, blacks and Hispanics. There's no specific treatment for acanthosis nigricans. Treatment of underlying conditions may restore some of the normal color and texture to affected areas of skin.

Absence seizure (petit mal seizure)

Absence seizure — also known as petit mal — involves a brief, sudden lapse of consciousness. Absence seizures are 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.

Compared with other types of epileptic seizures, absence seizures appear mild. But they can be dangerous. Children with a history of absence seizure must be supervised carefully while swimming or bathing because of the danger of drowning. Teens and adults may be restricted from driving and other potentially hazardous activities.

Absence seizures usually can be controlled with anti-seizure medications. Some children who have absence seizures also have grand mal seizures. Many children outgrow absence seizures in their teen years.

Abdominal aortic aneurysm

An abdominal aortic aneurysm is an enlarged area in the lower part of the aorta, the major blood vessel that supplies blood to the body. The aorta, about the thickness of a garden hose, runs from your heart through the center of your chest and abdomen. Because the aorta is the body's main supplier of blood, a ruptured abdominal aortic aneurysm can cause life-threatening bleeding.

Depending on the size and rate at which your abdominal aortic aneurysm is growing, treatment may vary from watchful waiting to emergency surgery. Once an abdominal aortic aneurysm is found, doctors will closely monitor it so that surgery can be planned if it's necessary. Emergency surgery for a ruptured abdominal aortic aneurysm can be risky.