Bird flu (avian influenza) is an infection from a type of influenza (flu) virus that usually spreads in birds and other animals. Sometimes, humans can get bird flu from infected animals. Like the versions of flu that people usually get, bird flu can make you severely ill. It’s extremely rare for it to spread from person to person. You might hear about bird flu when there’s …

Ataxia describes poor muscle control that causes clumsy movements. It can affect walking and balance, hand coordination, speech and swallowing, and eye movements. Ataxia usually results from damage to the part of the brain called the cerebellum or its connections. The cerebellum controls muscle coordination. Many conditions can cause ataxia, including genetic conditions, stroke, tumors, multiple sclerosis, degenerative diseases and …

Atelectasis (pronounced at-uh-LEK-tuh-sis) is the collapse of one or more parts of the lung. It specifically affects the small air sacs called alveoli. When you breathe in, your lungs fill up with air. The air travels to sacs in your lungs (alveoli), where the oxygen moves into your blood. The blood delivers the oxygen to organs and tissues throughout your …

Athlete’s foot is a common fungal infection (caused by a fungus). Athlete’s foot causes an itchy, stinging, burning rash on the skin on one or both of your feet. Athlete’s foot is most common between your toes, but it can also affect the tops of your feet, the soles of your feet and your heels. Your skin may become scaly …

Atopic dermatitis is a chronic condition that causes itchy skin that gets dry and scaly. It tends to come and go and may only be in childhood or may affect you your entire life. In people with light-colored skin, atopic dermatitis looks like red rashes. People with darker skin may develop brown, purple or gray rashes. Atopic dermatitis vs eczema: …

Atrial flutter is a common type of supraventricular arrhythmia. This means it’s an abnormal heart rhythm that starts in the upper chambers of your heart. With atrial flutter, your heart beats in a fast but consistent pattern. Faulty electrical signals cause this to happen. A normal heart rate is 60 to 100 beats a minute when you’re at rest. Atrial flutter can make your heart’s upper …

An atrioventricular (AV) canal defect is a congenital (present at birth) heart condition. It describes a group of several heart issues, including a hole in the wall (septum) at the center of your heart and problems with the way your heart’s valves work. Having a hole in the wall that separates the right and left sides of your heart is like a pipe with a …

Atrioventricular nodal reentry tachycardia (AVNRT) is a type of irregular heartbeat, also called an arrhythmia. It is the most common type of supraventricular tachycardia (SVT). People with AVNRT have a very fast heartbeat that often starts and ends suddenly. In AVNRT, the heart beats more than 100 times a minute. The condition is due to a change in heart signaling. …

Vaginal atrophy is a condition where the lining of your vagina gets drier and thinner. This results in itching, burning and pain during sex, among other symptoms. The condition also includes urinary tract problems such as urinary tract infections (UTIs) and urinary incontinence. Vaginal atrophy most often occurs during perimenopause and menopause when your ovaries produce less estrogen. It can occur in younger women and people assigned female at birth (AFAB) when their estrogen …