An aneurysm is a weak or expanded part of an artery, like a bulge in a balloon. Your arteries are large blood vessels that carry oxygenated blood from your heart to other parts of your body. If an area in an artery wall weakens, the force of blood pumping through can result in a bulge or aneurysm. Aneurysms usually aren’t painful. You …

Antibiotic-associated diarrhea refers to passing loose, watery stools three or more times a day after taking medications used to treat bacterial infections (antibiotics). About 1 in 5 people who take antibiotics develop antibiotic-associated diarrhea. Most often, antibiotic-associated diarrhea is mild and requires no treatment. The diarrhea typically clears up within a few days after you stop taking the antibiotic. More-serious …

Angelman syndrome is a rare, complex neurodevelopmental condition that primarily affects your nervous system. It’s caused by issues with a specific gene called UBE3A. Your nervous system is your body’s command center. Originating from your brain, it controls your movements, thoughts, behaviors and automatic responses to the world around you. Characteristic features of Angelman syndrome include: Developmental delay that’s often noticeable by six …

Antiphospholipid syndrome (APS) is a condition that makes your body much more likely than usual to form blood clots. Healthcare providers sometimes call it antiphospholipid antibody syndrome. The blood clots from APS can cause severe, life-threatening complications like strokes. They can also make pregnant people much more likely to experience miscarriages and other pregnancy complications. APS is an autoimmune disease. Autoimmune diseases happen when your immune …

Angina is chest pain or discomfort that happens when your heart isn’t receiving enough oxygen-rich blood. As a result, your heart may beat faster and harder to gain more blood, causing you noticeable pain. Angina isn’t a disease. It’s a symptom and a warning sign of heart disease. About 10 million people in the U.S. experience angina. So, if you have this …

Antisocial personality disorder (ASPD) is a mental health condition that can affect the way you think and interact with others and lead you to: Manipulate or deceive people. Exploit or take advantage of someone else for your own benefit. Disregard the law or the rights of other people. Feel no remorse for your actions. It’s common for people diagnosed with ASPD to …

Anal cancer (also known as carcinoma of the anal canal) develops in your anus’ tissues or the lining of your anal canal. Your anal canal connects your anus (the opening) to your rectum (the lower part of your digestive system). Your anus is where poop leaves your body. Healthcare providers can cure anal cancer if they detect and treat it early on. Types of anal cancer There …

Hives — also known as urticaria (ur-tih-KAR-e-uh) — is a skin reaction that causes itchy welts that range in size from small spots to large blotches. Hives can be triggered by many situations and substances, including certain foods and medications. Angioedema can arise with hives or alone. It causes swelling in the deeper layers of skin, often around the face …

Generalized anxiety disorder (GAD) is a mental health condition that causes fear, worry and a constant feeling of being overwhelmed. It’s characterized by excessive, frequent and unrealistic worry about everyday things, such as job responsibilities, health or chores. It can affect children and adults. GAD is one of several anxiety disorders. Most people with GAD have one or more other psychiatric …

An anal fissure is a crack or tear in the lining of your anal canal. It’s a common cause of anal pain and rectal bleeding, especially during bowel movements (pooping). Anal trauma usually causes a fissure, especially from straining to pass hard stools. Anal fissures can occur suddenly or gradually. They can also heal quickly or slowly. Are anal fissures common? Anal fissures …