This potentially serious condition can occur with few or no symptoms. Know the risk factors.
Disease
Dehydration
The body not having enough water and other fluids is very risky for infants, young children and older adults.
Disease
Delayed ejaculation
Learn what can cause delayed or absent ejaculation and how it can be treated.
Disease
Delayed sleep phase
Learn more about this sleep condition that causes a delay in usual sleep patterns.
Disease
Delirium
Learn what may cause this change in mental abilities. Symptoms develop fast and include confusion and being unaware of surroundings.
Disease
Dementia
This group of symptoms with many causes affects memory, thinking and social abilities. Some symptoms may be reversible.
Disease
Dengue fever
Learn how to identify the symptoms of this serious, mosquito-borne infection and how to protect yourself from infection.
Disease
Depersonalization-derealization disorder
This mental health condition causes you to feel like you're seeing yourself from outside your body or that things around you are not real, or both.
Disease
Depression (major depressive disorder)
Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest and can interfere with your daily functioning.
Disease
Dermatitis
Learn about the symptoms, causes and treatments of this itchy skin condition that affects children and adults, and about how moisturizers help prevent it.
Disease
Dermatofibrosarcoma protuberans
Learn about symptoms and diagnosis for this rare type of skin cancer. DFSP treatments include Mohs surgery, radiation and targeted therapy.
Disease
Dermatographia (Dermatographism)
Learn about the symptoms, causes and treatment of this skin condition in which light scratching causes raised lines or welts.