Diseases and Conditions

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

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All conditions that start with the letter M
  • Mad Cow Disease

    Mad cow disease is an extremely rare disease spread by eating beef from a diseased cow. It progresses quickly and…

  • Malaria

    Malaria is a serious disease caused by a parasite. The parasite is carried by one type of mosquito. Humans get…

  • Male Breast Cancer

    Breast cancer is a type of cancer that begins in the breast. Men can get breast cancer even though it…

  • Mallet Finger

    Mallet finger is an injury to your fingertip that makes it hard to straighten the finger. It is common in…

  • Mass Psychogenic Illness

    Mass psychogenic illness is when people in a group start feeling sick at the same time, but there is no…

  • Mastitis

    Mastitis is an inflammation of the breast, usually caused by an infection. It can cause breast pain, tenderness, and flu-like…

  • Mastocytosis

    Mastocytosis is the abnormal accumulation of mast cells, which protect the body from infection. It can cause rashes, nausea, diarrhea,…

  • Measles

    What is measles? Measles (also called rubeola) is a serious respiratory illness. This means it affects the lungs and breathing tubes. It also causes a rash and a fever. It is a very contagious disease. It can be spread to others very easily. In

  • Meckel's Diverticulum

    A Meckel’s diverticulum is a small pouch on the wall of the lower part of the small intestine. It is…

  • Meconium Aspiration Syndrome (MAS)

    Meconium aspiration syndrome happens when a newborn inhales meconium and amniotic fluid before, during, or after labor and delivery.

  • Melasma

    Melasma is a common skin condition that causes brown patches to appear on the skin, usually on the face.

  • Meniere’s Disease

    Meniere’s disease is a chronic disorder in your inner ear.

  • Meningitis

    Bacterial and viral meningitis cause the tissue around your brain and spinal cord to swell. Bacterial meningitis can cause brain…

  • Menopause

    Menopause is when a woman’s menstrual periods permanently end. It happens because, as a woman ages, her ovaries make fewer…

  • Metabolic Syndrome

    Metabolic syndrome is the term used to describe a set of risk factors for heart disease. These include high blood…

  • Methicillin-resistant Staphylococcus aureus (MRSA)

    Methicillin-resistant Staphylococcus aureus (MRSA) is a subset of bacterial (staph) infection of the skin.

  • Microscopic Hematuria

    Microscopic hematuria means you have red blood cells in your urine. These blood cells are so small, though, you can’t…

  • Migraines

    Learn about the different kinds of migraine headaches and their symptoms and treatments.

  • Mitral Valve Prolapse

    Mitral valve prolapse affects your heart. It happens when the mitral valve flaps don’t close properly and blood leaks from…

  • Mononucleosis (Mono)

    Mononucleosis is a contagious illness usually spread through saliva. For this reason, it’s sometimes called “kissing disease.”