Rare skin diseases are often confined to isolated sections of the world population. Many doctors, including dermatologists that specialize in the treatment of the skin, can spend their entire careers never encountering a single example of the hundreds of types of rare skin diseases that exist. This is due to the fact that they usually only occur in a handful of people for every million people in the human population. These diseases include Recessive Dystrophic Epidermolysis Bullosa (RDEB), Tinea imbricata or Tokelau ringworm, found only in the Mindanao tribe of the Philippines, and Stevens-Johnson Syndrome (SJS) that occurs as an adverse reaction to drugs and is only seen in a handful of people per million. Rare disorders of the skin can have genetic, environmental or unknown causes, and, though many have no known cure, some are easily treatable once identified.
Morgellons is an example among rare skin diseases of one that is poorly understood, but believed to be caused by some sort of infection. It causes skin lesions as well as other adverse effects such as memory loss and joint pain, and has been identified in roughly 2,000 to 4,500 people within the US population of 307,000,000 as of 2011. Like several rare skin diseases, there is no known cure for Morgellons, which was first identified in 2001 by Mary Leitao, the mother of a two-year-old child that contracted it in Pennsylvania, US.
Within the Mindanao tribe of the Sarangani province of the Philippines, Tinea imbricata is caused by a fungal infection of the Tokelau ringworm. It produces a sort of scaly, fingerprint-like pattern of skin exfoliation that can spread to large parts of the body, but which responds to conventional treatments when identified. As of the year 1990, only three cases of the disease had been reported worldwide, with one stretching back to as far as the year 1789. At least 28 individuals have been discovered to be infected with the disease as of the year 2011, however, and all new cases have been within the Mindanao tribe.
RDEB was an example among rare genetic diseases of an incurable condition until 2010, when 10 children were treated for it in the US with stem cells obtained from bone marrow. The disease of RDEB has been diagnosed as occurring in about 20 newborn babies in the United States for every 1,000,000 live births, and an international effort by doctors from the US, UK, and Japan have been working on treatments and possible cures for it as of 2010. While eight of the 10 children recovered, two died, and medical research is ongoing to improve treatment methods. Like many rare skin diseases, RDEB is known to primarily affect children because its results can be so severe that they usually result in an early death. The disease makes the skin very sensitive to friction, causing it to blister and scrape off, and this effect also occurs in interior skin surfaces such as in the mouth and esophagus, which can result in extreme pain for such basic activities like eating.