Diseases and Conditions

Find doctor-approved information about symptoms, causes, diagnosis, treatment and prevention of common diseases and conditions.


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  • Active woman in her 50s running and jogging.


    Perimenopause is a stage in a woman’s reproductive years that occurs just before menopause.

  • Peripheral Arterial Disease and Claudication

    Peripheral arterial disease (PAD) is a problem with blood flow in the arteries, especially those in the legs. Claudication is…

  • Peritonsillar Abscess

    A peritonsillar abscess is a collection of pus near one of your tonsils. It can be caused by an infection…

  • Sad-looking young woman with dysthymic disorder, or PDD, looks down while holding a mug.

    Persistent Depressive Disorder (PDD)

    Persistent depressive disorder is a mild or moderate depression that can last at least 2 years. It can be treated…

  • Peyronie’s Disease

    Peyronie’s disease is the buildup of fibrous scar tissue in the penis, causing it to curve.

  • A sleeping baby lays wrapped in a blanket. Phenylketonuria (PKU) is a rare genetic condition where babies are unable to break down an amino acid. This can lead to brain damage.

    Phenylketonuria (PKU)

    Phenylketonuria (PKU) is a rare genetic condition where babies are unable to break down an amino acid. This can lead…

  • Pica

    Pica is a compulsive eating disorder in which people eat nonfood items. Dirt, clay, and flaking paint are the most…

  • Pigmented Villonodular Synovitis

    Pigmented villonodular synovitis is a joint problem that usually affects the hip or knee. It also can occur in the…

  • A pilonidal cyst is a small, protruding sac near the tailbone at the top of the buttocks crease. Ingrown hairs commonly cause pilonidal cysts.

    Pilonidal Cyst

    A pilonidal cyst is a small, protuding sac located near the tailbone at the top of the buttocks crease.

  • Pinworm Infection

    Pinworm infection is an intestinal infection caused by small, white worms. Anyone can get it, but it’s most common in…

  • Piriformis Syndrome

    Piriformis syndrome is a condition that causes pain or numbness in your buttocks, hip, or upper leg when the piriformis…

  • Zoomed out and zoomed in view of the brain’s pituitary gland

    Pituitary Tumors

    The pituitary gland is located in your brain and produces hormones. Most pituitary tumors are non-cancerous.

  • Pityriasis Rosea

    Learn about the symptoms and causes of pityriasis rosea, and how it is diagnosed and treated.

  • A baby girl wearing a medical helmet who has plagiocephaly smiling at the camera


    Plagiocephaly is a condition where your baby’s head has a flat spot or is misshapen.

  • A woman rubs her heel to relieve plantar fasciitis symptoms.

    Plantar Fasciitis

    Plantar fasciitis is an inflammatory condition that causes pain and swelling in your heel.

  • Lung Symptoms

    Pleurisy (Pleuritis)

    Pleurisy is a medical condition that affects the lining of your lungs and chest, which can become irritated with the…

  • A doctor listens to a patient’s lungs with a stethoscope. Pneumonia is an infection of the lungs usually caused by bacteria or a virus. Walking pneumonia is a mild case of pneumonia.

    Pneumonia and Walking Pneumonia

    Pneumonia is an infection of the lungs. How serious it is depends on what caused the pneumonia, your age, and…

  • Poison ivy is a type of toxic plant that can cause an itchy rash. Poison ivy often grows low to the ground, resembling a weed or shrub.

    Poison Ivy

    Poison ivy is a type of toxic plant. It is common in most parts of the United States. Poison ivy…

  • Poisoning

    Poison is any substance that is harmful to your body. You could breathe it in, swallow it, or absorb it…

  • An illustration of a healthy kidney and a kidney with cysts

    Polycystic Kidney Disease

    Polycystic kidney disease (PKD) is an inherited disease that affects the kidneys. It causes abnormal sacs of fluid (called cysts)…