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
  • cows peaking their heads out of their stalls in a barn

    Mad Cow Disease

    Mad cow disease is the common name for a rare and deadly brain disease. The disease is spread by eating…

  • A mosquito sits on human skin


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

  • Close-up of a pink ribbon (the symbol of breast cancer awareness) in a man’s hands

    Male Breast Cancer

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

  • close-up of a young man in jeans holding a baseball in his hand

    Mallet Finger

    Mallet finger is an injury to your fingertip that prevents you from straightening it. It is common in sports, especially…

  • colleagues wear protective facemasks during a meeting at work

    Mass Psychogenic Illness

    Mass psychogenic illness is when people in a group start feeling sick at the same time with no physical or…

  • a mother breastfeeds her baby


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

  • A woman with hives on the backs of her legs


    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

  • Small intestine in detail illustration

    Meckel's Diverticulum

    Meckel’s diverticulum is a small pouch on the wall of the lower part of the small intestine that can cause…

  • Nurse holding newborn

    Meconium Aspiration Syndrome (MAS)

    Meconium aspiration syndrome affects newborns who inhale their stool and/or amniotic fluid before, during, or after labor and delivery.

  • close-up of a person’s cheek with small patches of melasma


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

  • A young woman covering her ears and squeezing her eyes shut

    Meniere’s Disease

    Meniere’s disease is an inner ear problem that can cause dizziness and ringing in the ears but is not contagious…

  • Cotton swab with fluid sample for lab test to diagnose meningitis


    Meningitis is swelling of the tissue around your brain and spinal cord. There are two common types of meningitis: viral…

  • Menopause

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

  • A close-up of a woman pinching fat on her stomach

    Metabolic Syndrome

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

  • two doctors in scrubs washing hands

    Methicillin-resistant Staphylococcus aureus (MRSA)

    Methicillin-resistant Staphylococcus aureus, or MRSA, is a bacterial infection of the skin that can cause bumps, swelling and pain and…

  • A laboratory rack with several tubes of urine ready for analysis

    Microscopic Hematuria

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

  • Woman with headache in front of blurry surroundings


    Migraines are headaches that can be intense and reoccurring.

  • doctor using stethoscope to listen to woman’s heart

    Mitral Valve Prolapse

    Mitral valve prolapse is a heart condition in which the flaps of the mitral valve don’t close properly. Most people…

  • Monkeypox

    Monkeypox began making the news following a surge in new cases in summer 2022. This outbreak includes reports of cases in several countries where monkeypox hadn't been seen before. This includes the United States. In July 2022, the World Health Organization (WHO) announced