In-depth

Acute sinusitis

Acute sinusitis occurs when your sinus cavities become inflamed. Antibiotics, decongestants and corticosteroids may relieve pain and congestion and prevent development of chronic sinusitis.

Allergies

Allergy symptoms can make you miserable and in some cases, they're life-threatening. Here's some information about allergies — and tips on treating allergy symptoms.

Asbestosis

Asbestosis is a lung disease resulting from prolonged exposure to asbestos, a product once commonly used in the building and manufacturing industries.

Ascariasis

Ascariasis is a common type of roundworm infection found worldwide. It's spread by poor hygiene and improper sanitation. Infections are effectively treated with medication.

Asthma attack

Asthma attack: Find out what the symptoms are and how to treat an asthma attack.

Atelectasis

Atelectasis, or collapsed lung, is a possible complication of many respiratory conditions. Find out what causes it and how it's treated.

Barrett's esophagus

Barrett's esophagus is caused by repeated, long-term exposure of the esophagus to stomach acid. The condition can sometimes lead to cancer.

Bile reflux

Bile reflux — the backwash of bile from the small intestine into the stomach and esophagus — can cause ongoing inflammation and lead to serious complications.

Bird flu (avian influenza)

A type of influenza normally found in birds, bird flu first appeared in humans in 1997. Experts worry it could lead to a flu pandemic.

Bronchitis

Bronchitis often develops after a cold. Learn how to prevent this potentially serious lung infection.

Cancer

Learn about cancer, what it looks like and what causes it.

Castleman disease

Castleman disease is a rare illness that affects your lymph nodes and other immune-cell structures of your body.

Chronic sinusitis

Chronic sinusitis involves long-term inflammation or infection of the sinus cavities. Medications can help, and in rare cases surgery can treat this painful condition.

Churg-Strauss syndrome

Churg-Strauss syndrome is a rare disorder marked by blood vessel inflammation that affects organs throughout the body. Asthma is the most common sign.

Common cold

You've got a cold, or you're trying to prevent getting one. Here are some timely tips.

Common cold in babies

Do you feel as if you're constantly wiping your baby's nose? Learn to recognize, treat and prevent the common cold.

Croup

The barking cough of croup can be scary. But it's usually not serious and gets better with rest and fluids.

Dilated cardiomyopathy

Dilated cardiomyopathy is a disease of the heart in which the heart's main pumping chamber becomes enlarged and doesn't pump blood efficiently.

Dust mite allergy

Dust mite allergy, an immune system reaction to inhaled dust mite "debris," causes hay fever symptoms and may cause allergy-induced asthma.

Dysphagia

Difficulty swallowing can be painful and may indicate a serious medical problem.

Ebola virus and Marburg virus

Egg allergy

Egg allergy can cause a serious reaction in children and adults. Here's how to recognize egg allergy symptoms, and what to do if a severe reaction occurs.

Ehrlichiosis

Ehrlichiosis is a tick-borne disease that causes flu-like symptoms. When you're outdoors, be aware of steps to prevent tick bites.

Enlarged heart

Enlarged heart is often a sign of a serious heart condition. Find out causes and treatments for enlarged heart.

Esophageal cancer

Reduce your risk of esophageal cancer by eating more fruits and vegetables.

Esophagitis

Several conditions can cause esophagitis. Learn what they are and how to get relief.

GERD

Goiter

Goiter is an enlargement of the thyroid gland due to a variety of causes. The condition can cause difficulty swallowing or breathing.

Group B strep disease

A common bacterium, group B strep may cause serious illness, especially in newborns, older adults and people who have certain chronic health conditions.

Hantavirus pulmonary syndrome

Hantavirus pulmonary syndrome is initiated by a rodent-carried virus that infects the lung tissues, bringing on flu-like symptoms, respiratory problems and even death.

Heart disease

Heart disease, usually thought of as blockages in the arteries that can cause a heart attack, can describe any medical condition affecting your heart.

Heart failure

Heart failure means your heart can't efficiently pump blood throughout your body. Medications, and sometimes devices or surgery, can help you manage this condition.

Heart murmurs

This whooshing sound in your heart is usually harmless, but in some cases heart murmurs can alert your doctor to specific heart conditions.

Histoplasmosis

The fungus that causes the lung disease histoplasmosis lurks in soil, chicken coops and caves. Find out if you're at risk.

HIV/AIDS

More than 39 million people are living with HIV — the virus that causes AIDS. Millions more are likely to become infected in the next decade.

Hodgkin's lymphoma

Hodgkin's lymphoma (Hodgkin's disease) is cancer of the lymphatic system. Many early symptoms of this cancer resemble those of the flu.

Influenza (flu)

Don't let the flu set you back. Find out how to protect yourself from getting sick with the flu.

Laryngitis

Lost your voice? Laryngitis is usually short-lived, and the cause is often simple. But prolonged hoarseness can signal a more serious condition.

Legionnaires' disease

Legionnaires' disease, a severe form of pneumonia, is caused by bacteria that can live in water in air conditioning systems, showers and spas.

Lung cancer

Smoking increases your risk of lung cancer. Quit now and reduce your risk.

Mesothelioma

Mesothelioma is a type of cancer closely linked to asbestos exposure. Find out the signs and symptoms of malignant mesothelioma and how to protect yourself.

Milk allergy

Milk allergy can cause hives, wheezing and gastrointestinal problems. Avoidance is the primary treatment, but the good news is that many children outgrow milk allergy.

Mitral valve regurgitation

Mitral valve regurgitation occurs when blood flows backward in your heart because the mitral valve closes improperly.

Mitral valve stenosis

In mitral valve stenosis, the mitral valve is narrowed, obstructing blood flow between the chambers on the left side of the heart.

Non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma is cancer originating in the lymphatic system. It's caused by abnormal white blood cells, and often the only sign is swollen lymph nodes.

Pericardial effusion

Pericardial effusion, the accumulation of excess fluid in the sac-like structure around the heart, can decrease heart function and can be life-threatening.

Pleurisy

Pleurisy is the painful inflammation of the membranes that surround your lungs. The cause can be one of a number of underlying conditions.

Pneumonia

There are at least 50 kinds of pneumonia — a serious lung infection that takes the lives of more than 60,000 Americans every year.

Pneumonitis

Pneumonitis is a general term for lung inflammation. It can cause difficulty breathing, often accompanied by a cough.

Pulmonary embolism

Pulmonary embolism occurs when one or more arteries in your lungs become blocked. Surgery, cancer, family history and long airplane trips may place you at risk.

Pulmonary fibrosis

Pulmonary fibrosis results from scar tissue that forms in your lungs. This affects your ability to breathe and obtain enough oxygen.

Roseola

Roseola is a common infection of childhood. The condition causes a fever that lasts several days, followed by a rash on the trunk and neck.

Sarcoidosis

Sarcoidosis starts in your lungs but can cause inflammation in any part of your body. It can last a lifetime, or disappear in a few years.

Severe acute respiratory syndrome (SARS)

Severe acute respiratory syndrome (SARS) has sickened people worldwide. Although effective treatments aren't yet available, common-sense precautions may help you avoid infection.

Sinus headaches

Sinus headaches are often confused with migraines. Proper diagnosis and treatment are the keys to relief.

Spinal cord injury

A spinal cord injury affects the nerves that carry impulses to and from your brain. Permanent disability commonly results.

Stevens-Johnson syndrome

Stevens-Johnson syndrome is a disorder of the skin and mucous membranes. Often, this severe adverse reaction is caused by medication or an infection.

Swine flu (H1N1 flu)

Swine flu — Comprehensive overview covers swine flu symptoms, tests, treatment and prevention.

Thoracic aortic aneurysm

Throat cancer

The most common throat cancers are linked to smoking and excessive alcohol use.

Tuberculosis

Tuberculosis (TB) is making an alarming comeback. You're especially at risk if you have a weakened immune system.

Tuberous sclerosis

Tuberous sclerosis is a rare genetic disease. With appropriate treatment, many people who have tuberous sclerosis lead full, productive lives.

Tularemia

Tularemia is a rare, highly infectious disease spread by insects and wild animals. Landscapers, hunters and laboratory workers are especially at risk.

Valley fever

Valley fever — This common fungal infection in America's desert regions causes few, if any, problems for most people, but for some it can be life-threatening.

Wegener's granulomatosis

Wegener's granulomatosis is an uncommon disease that causes blood vessel inflammation that can damage lungs, kidneys and other organs. Untreated, it can be fatal.

Whipple's disease

Whipple's disease is a rare bacterial infection that affects primarily the gastrointestinal system, and can be treated successfully with antibiotics.

Whooping cough

Whooping cough is a serious lung infection that's especially dangerous in young infants.

May. 24, 2013