Background: \- Skin disease can have many causes. It can have widespread consequences, and in rare cases can lead to death. Researchers want to determine the causes of various types of skin diseases and find a way to treat them.

Objectives: \- To determine the causes of various skin diseases and find ways to treat them.

Eligibility: * People ages 2 and older who have: * A skin disease or at risk of developing a skin disease OR * A family member of persons with a skin disease * Healthy volunteers ages 2 and older

Design: * Participants will be screened under a separate protocol. * Participants may take a survey about how their skin condition affects their quality of life. * Participants will have a medical history and a physical exam including a detailed skin exam. Pictures will be taken of their skin to document any skin disease. * Participants will have specimens collected. This may include: * Several teaspoons of blood taken at each visit * Stool samples * Nail and body fluid (like saliva) samples * Cheek swabs. The inside of the cheek will be scraped for about a minute in each direction to collect cells. * Collection of skin samples with: * A swab (like a Q-tip) * Gently scraping skin to remove the outer layers of cells * Applying and removing 1-inch pieces of tape * Participants may have up to 4 skin biopsies in 12 months, with 4 separate biopsies taken each time. * An area of skin will be numbed with an injection. * A piece of skin the size of a pencil eraser will be removed using a small instrument. * A flat scar usually develops at the biopsy site.